Blog Indexing Question: My ranking for my core keyword went up, but most of my site was recently put in Google's Supplemental Index, and I saw my income and traffic drop sharply. I have not built any links recently or made any changes to my site. How can I fix this and get my site top rankings again?
Answer: Google has been tightening down on their duplicate content filters. They have also been using PageRank scores to determine whether to index a page, if they should stick it in their supplemental results, and perhaps how strongly they should apply various filters (such as duplicate content filters).
Between slightly lower internal PageRank scores (minor issue) and increasingly aggressive duplicate content filters (major issue) and significant duplication from page to page on your site (major issue) much of your site is in Google's supplemental index.
In general, the best way I know of to move sites from more supplemental to normal is to get high-quality links (donâ€™t bother to get low-quality links just for linksâ€™ sake).
Since you said you have not built links in a great deal of time and few people are talking about your site in the active parts of the web the key is to write more about things that people are talking about or would comment on. Great content helps build links. You have to keep blogging if you want to keep your mindshare up.
Others pointing more link equity at your site from external sources should help improve your PageRank scores. PageRank is a large part of what is used to determine if a page is of high enough quality to stay indexed (or put in the supplemental index), and how aggressively duplicate content filters (and other filters) should be applied against it.
If you get strong editorial deep links from other bloggers that should also help search engines crawl that portion of your site better to make up for any information architecture related issues that may be causing certain portions of your blog to be inadequately crawled.
Make Longer Posts:
Since your posts tend to only be a sentence or two long, most of the pages are rather similar to each other. You may want to post more text in each post, and turn comments on to have more unique text on each page.
Reduce Sitewide Repetitive Features:
You need to make your page titles and meta descriptions unique on each page.
You may also want to resort your code order to put unique content higher in the page content and have duplicated and sitewide template related issues occur later on.
Don't Link at Garbage:
Since your site has a rather low PageRank you may want to only list your blogroll on your home page instead of every page of your blog. Take out other parts of your site that heavily duplicate each other from page to page. Also consider removing your sitewide links to some of the unimportant pages on your site to flow more of your link equity throughout your site.
I would also recommend removing the tagging pages on your site as your site is already navigable via your categories, and the tags create low value noise pages that reduce your link equity distributed on the quality pages. I also think it is foolish to link at all those auto-generated Technorati pages...that wastes a lot of your link authority. I would also recommend not linking to some of the pages you don't want Google to index, such as those printer friendly pages. You may also want to block those printer friendly URLs using the Robots.txt protocol.
You have canonical URL issues which can be fixed. If www.mysite.com and mysite.com are showing different PageRank scores 301 redirect the less popular version of your URL to the more popular version.
You also have a few broken links on your site that could be fixed.
All these changes should facilitate better indexing of your blog posts.
Issues for Commercial Sites:
Many commercial sites (especially thin product database sites) also fall into the Google Supplemental index. The above examples all apply to those types of sites, but in addition you could consider the following
add an editorial element to your site to improve your sitewide authority score
enable customer feedback and reviews to get more unique content on your pages
Keep in mind that if you do not do any offline marketing or much marketing outside of search, your site is more prone to large swings from search related fluctuations than some other sites which have more brand equity and/or do other forms of marketing.
SEO Question: When writing content for our websites what is the optimal copy length? Is page length important for search engine optimization?
Answer: Every page and every site is unique. There is no universal correct or incorrect answer to how much content is right.
Optimize For User Experience:
A page should not just be optimized for search. It should also be optimized for user experience. If you optimize just for search it could be to the detriment of your business.
One of my friends has most of their content on their home page. Because their homepage has most of the content and the most link equity it gets most of their traffic. They are afraid to move the content because they do not want to lose traffic, but if they moved the content they would probably maintain about the same amount of traffic, drastically improve their conversion rates, and do a better job of filtering the prospective clients.
Structure Your Ideas:
The content needs to be structured so that it is easy to consume. Use subheaders to make the content easy to consume. Also break pages into logical chunks that are easy to site or link at...don't write endless stream of mind random copy if you want people to read it.
Avoid creating low value near duplicate pages, as duplicate content filters are getting more aggressive.
Variation is Good:
Make sure there is variation amongst your pages so as not to set an unnatural pattern or give your writing arbitrary constraints. Some ideas take many words to express. Some take less. Real content sites do not have exactly 500 +/- 5 words on each page. Use as many words as necessary to express your ideas.
If you are trying to market a piece of content over-invest in ensuring it is of high quality. If you want your content to act as your marketing by being linkworthy make it appear comprehensive and well researched. If you are the first person with an idea make sure you do it well enough to spread your message far enough that you become synonymous with that idea.
Emphasize Your Style:
You also need to consider your personal style. Instapundit can write short snappy posts because Glenn Reynolds is a great writer who needs few words to convey his meaning, and tries to be first with the news. Some pages may have more credibility with less words on them. If a currency converter was given an obtuse name and had many keywords separated by commas in the footer it might make the tool look less credible and less trustworthy.
Good writing does not add extra words for the sake of word count. Each word carries purpose and meaning. I can tell when I haven't read books in a while because I notice my writing gets looser.
General Search Indexing Trends:
Getting content indexed is becoming a major hurdle. If you have forums and other noisy parts to your site it would be a good idea to have them segregated on a subdomain away from your higher quality and more in depth editorial quality content.
There are three general trends going on that make me think longer copy is better than shorter
Since Google's relevancy algorithms are looking more for natural writing, the value of having small hyper-focused pages is not as good as it once was...good copy gets just as much traffic for long tail keywords you didn't intend on optimizing for.
Google is getting stingier with how they crawl and what they are willing to index. If they will only index 100 pages for x units of PageRank then having nearly 100% of a 100 page site indexed is far better than having 40 or 50% of a 200 page site indexed.
On a philosophical level it also makes sense that search engines want to index richer content. The web is a series of incomplete thoughts. The more search engines can make people write in depth high quality content that provides complete answers the more they improve the value of Google. Search engines will try to push people toward writing more well thought out essays rather than empty me too cut and paste posts.
Content Suggestions Based on Publishing Formats:
A page which has 500 words on it will overlap many more keyphrases than two different pages that have 300 words each. As long as you can put your AdSense ads in a prominent position that gets a decent clickthrough rate without sacrificing your linkability I would recommend going with 500 to 600 word articles.
If you write naturally and your site gains a decent amount of authority you will end up accidentally ranking for many great keyword phrases that never showed up on keyword tools.
Site Selling CPM Ads:
If you are selling CPM ads that may favor breaking longer articles into many shorter pages so each read article gets more page views. This is especially true if you have a strong brand, great mindshare, great link equity, and many direct readers, like Wired.com.
Lead Generation Sites:
Focus your content on conversion, perhaps even using brief pages with little content, but ensure your content is unique. Get what legitimate links you can and add linkbait to your site to build up the authority of your site.
Do whatever you need to in order to keep your social currency. Use your market influence to push other profitable business ventures (perhaps indirectly). Only mention a few commercial offers, or place ads in a non-intrusive manner if you are in a competitive vertical and do not enjoy a large self reinforcing market position.
Site Selling Products and Services:
If you sell a commodity add some value to the transaction (consumer feedback, free shipping, brand, etc.) to make your shopping experience a non commodity.
In your content actively guide the user to do the desired goal. Home pages and other high profile pages should be targeted toward navigating users to the desired actions. Even your interior pages which are well integrated into a commercial site should be focused on conversion, building credibility, and filtering bad leads.
Get what legitimate links you can and add linkbait to your site to build up the authority of your site. If possible add consumer feedback.
How to Be Different:
Benefits of Consumer Feedback:
As noted in this study [PDF] consumer feedback adds credibility and trust which help make the online shopping experience feel more like the offline experience. Consumers also add content which makes your content unique relative to similar content from other merchants selling the same products. We tend to use language in similar patterns. Many consumers also misspell words, which helps you target many longtail keyword phrases.
Be First or Be Different:
Sometimes the easiest way to be first is to put a different spin on an idea. If you are the first with an idea push spreading it until you have enough market leverage for your ideas to spread themselves. On your best ideas do not rely on the market spreading it, use email, instant message, advertising, and other other tool at your disposal. Push your ideas to spread quickly because it is much harder to get people to link at your news when it is a couple days old. Put few or no ads on the ideas you want to spread until AFTER they have spread.
SEO Question: I have been submitting my articles to article directories and submitting my site to directory after directory, but I am not getting anywhere in the search results. What should I do to promote my SEO site and services?
Answer: Rankings do not matter.
The first thing you have to understand about getting good SEO clients (as in clients actually worth having) is that ranking is not the key to getting good clients. Building trust is the key. In fields which have a bad reputation (especially ones where there is high value and a lot of competition) you need to do more than just rank to sell. Here are four examples to back up this point of view.
Ranking for SEO Book sends me far more traffic than ranking for SEO. Most generic searches in the SEO industry are automated traffic, competitive research, and low quality leads.
When SeoBook.com did not rank for SEO Book for a while during an aggressive algorithm update that filtered out sites with too much similar anchor text my ebook sales were 85% of their prior month volume. Imagine selling almost the exact same amount of an ebook about ranking in search results when you don't even rank for your own brand name. That shows that my sales come mostly from recommendations, not search results.
ClientsideSEM is a new site and we have not marketed it aggressively, and the site does not rank for many keywords, yet we already get more leads than we can possibly handle.
I ranked in the top 10 for search engine marketing a few years ago and got very few leads from it. I didn't start getting many leads until I wrote a popular article about the Google Florida Update. Oddly enough, my rankings were worse when I was getting those leads, but because people were reading my stuff and talking about me I got more leads than I knew what to do with.
As an SEO you don't build enough trust just by ranking. And you don't build trust (or rankings) by getting an unlimited supply of garbage links on the edges of the web. The key to picking up clients is to be seen where the potential clients are. Participate in the active parts of the web and be seen as an expert. Submit articles to sites like WebProNews.
If you can come up for reasons people would want to talk about you then you will get more exposure than you can handle. There is still a lot of opportunity out there. For example, you can commission a study of fortune 500 websites to see which of them are using cloaking or IP delivery, and then market the hell out of it. If you do a good job a few weeks later you are suddenly one of the experts of SEO for fortune 500 websites.
Making the Invisible Visible:
SEO is largely painted as a bad hated field and SEO services are often viewed as an invisible service. If you know how to get people to talk about your brand and SEO you should be good at getting people to talk about other topics (for your clients) as well.
If you know how to make the invisible visible you have an endless supply of affordable quality links at your disposal.
And if you go to conferences and meet people in person it is far easier to build a solid trusting relationship. That is where the best potential SEO clients are, as they have capital, knowledge, and an interest in the topic. If they have enough resources to attend a conference they probably can afford to hire a good SEO too.
SEO Question: What is a reasonable price to pay for professional SEO services?
SEO Answer: There is never a cut and dry answer to the question, but typically the range should be somewhere along the amount of value it adds to your business. For example, if you are only paying a few hundred dollars and expect the person to add millions of dollars to your business, then you are also expecting them to be naive and ignorant to marketing and their market value.
If they are ignorant to marketing and their market value then the odds of them being a great marketer or providing great results are going to be pretty low. As SEO evolves it is becoming more about marketing and understanding markets. If an SEO can't sell themselves for a decent rate then how are they going to know your market well enough to integrate your business into your marketplace?
Good Marketing is an Investment:
An alternate angle to look at the price of SEO is to look at it from an investment standpoint. For many businesses it is a price outside of their reach because most SEOs do not offer much in the line of guarantees AND most sites are easy to clone. The easy to clone concept is one you don't hear discussed much because most businesses probably do not customers to think they would use potential customers for competitive research and niche discovery, but why wouldn't you?
Bad Marketing is a Cost:
I recently emailed back and forth with a new SEO who was trying to outsource the SEO on his own SEO service website. It is going to be hard to add value and understand how social networks work if you don't at least do it well on one of your own sites. But if a person does SEO for their own SEO site it makes it easier to visualize the hubs and authorities in other markets.
When you hire someone you are paying them both to work and to learn. If they are well versed in their trade they are learning how to apply what they know about their industry to your business. If they are not you are paying them to (at least try to) learn about their industry. I write that both as a person who has been paid a premium to apply trade knowledge, and as a person who provided lower value services as a low price point while getting paid to learn.
What Value Does Your Business Offer?
If I can have no interest in a topic, start from scratch, and clone the market position of a business in under a week then they have not done a good job of building value on their end, and if I have to add near endless value to their business for their business to have any value at all I am better off creating a similar site myself, such that
I can work on it whenever I want
I can market it as aggressively as I want
I can add value where the client was unwilling to because they thought it was too risky
if it looks like it is going to fail I can stop working on it at any time
I don't have client approvals slowing me down
I keep all the profits
it can create a passive recurring revenue stream
even if it does fail I can use the site for nepotistic reasons down the road
When you think about it over half the businesses around the world are probable just arbitrage plays (depending on how loosely you define arbitrage). The difference between SEO and most other arbitrage business models is that SEO is cheaper, more targeted, and more scalable. But it only stays scalable and fun if you realize the value of what you do and place yourself high on the value chain.
If a business does not add much real value and is easy to replicate then they should view everyone they talk to as a potential competitor, at least until their business has some tangible value that takes significant investment to replicate.
As an SEO or affiliate marketer one of the first questions you have to ask when evaluating a competitive market or potential customer is how hard would it be to clone what they are doing. If a business is easy to clone you are probably better off just creating your own business that would be harder to clone, outrank them, and then sell leads.
SEO Question: Our site has an about us section which links to press coverage of our site. We are worried about bleeding PageRank, and are wondering if we should use nofollow on our links.
Answer: The worry about bleeding PageRank is probably a bit dated in nature. It is based upon thinking that you have a finite amount of PageRank, and that if you link out to other sites you are wasting your PageRank, but truth be told most good sites have both inbound links and outbound links. And you shouldn't be afraid of a few reciprocal links with large trusted media sites either...as reciprocation is part of the natural link structure of the web, and linking out to trusted sites helps associate your site with other high quality sites.
The goal of public relations is to get people to view your company the way you want it to be viewed, and to get people to talk about your topic and your company from your perspective using your language and metrics.
If you make the mainstream media, it generally has the following effects:
Improved credibility with the media, which makes it easier for the media to review your products / cite you / interview you again (if you show you were trusted in the past it is easier to trust you again).
increased trust with other link sources on the web - for example, the Wikipedia notability guidelines include "The company or corporation has been the subject of multiple non-trivial published works whose source is independent of the company or corporation itself."
When people who do not know your subject write about your subject they will likely trust many of the same sources that the media has (see Wikipedia mention above).
If few people in your market make the news when someone makes the news it may be considered linkworthy.
If the subject that causes you to make the news is a big deal many links will flow. When I made the Wall Street Journal that also got coverage on sites like Slashdot. I also mentioned it on my blog and even more people mentioned it.
Increased trust in the minds of consumers and many members of your market.
Increased mindshare and share of voice in your marketplace.
In addition to the above obvious side effects of media exposure you can also further leverage that exposure. Many media sites have strong domain related trust, and thus rank easily in the search results if they have even modest link equity pointed at them.
When people search for your company name which is a better set of search results:
another conspiracy theory about your company
random (could be good or bad or competition)
random (could be good or bad or competition)
news article you helped promote
another news article you helped promote
random (could be good or bad or competition)
In any case, you will likely have some results that are bad or out of your control, but if you link at pages that talk about you in a positive light you are helping those pages be fairly represented or overrepresented in the search results.
Consumers, consumer advocates, raged consumers, and journalists researching your company will research you and your company on Google. When people say nice things about you it helps to make it easy for others to find, and that also helps bury some of the negative stuff.
When you link to a news site you are mentioning it on your site because you trust it. When you use a nofollow to link to a news site you are saying you do not trust it. If you don't trust the people who are talking positively about you then it is going to be an uphill battle.
SEO Question: A top ranked competitor of mine has a few good links, and many low quality links. I don't think they should be ranking, but they are. Should I duplicate what they are doing?
SEO Answer: As an SEO I think you can learn more from seeing top ranked results that should not be ranking where they are than from sites you expect to rank, but far too many people desire to emulate those rankings without building the necessary criteria to rank.
Sure it makes sense to look at high ranking sites which shouldn't be ranking, and try to get some of their best links, but it is probably not worth replicating everything they are doing (including all of their reciprocal links and low quality links). You can't replicate their age with a new site (and there may be other criteria that you do not see and thus can not replicate), if your link profiles are too well aligned their site will probably get filtered out of the search results, and if their rankings are not stable you have little to gain by replicating what they are doing.
A friend of mine tried to get me to do a $750 per month ad buy on a ghetto top ranked site. I said no to them. The next month the ghetto site dropped off in the search results and our ranking is already higher than theirs (on a similar spend) by going after higher quality links.
It is far more valuable to notice the trends as to where the algorithms are headed and push in that direction. Find the sites that are ranked which should be, and where possible, try to make your site profile align with those sites.
SEO Question: Is a Yahoo! Directory registration worth it? How do I know what directories are worthwhile? What directories should I submit to? Do you have any good site submission tips?
SEO Answer: If you have a business, and are serious about SEO, I generally would recommend submitting your site to the Yahoo! Directory. There are a lot of criteria to consider.
Your Site Name:
If your site name is MyKeywords.com make sure that your site lists your company as My Keywords. Do not run the words together in your logo, in your page title or text, or in the title of your directory submission when submitting your site to important directories. By separating the words in your site name you get better anchor text because the search engine sees the separate words in your links. Descriptive links from trusted editorial sources can be seen as a sign of quality.
If your keywords do not look like they are part of your official branded site name do not get too aggressive with keyword stuffing unless you are willing to risk a Yahoo! Directory editor editing your business name and potentially giving you less than ideal anchor text.
When I buy quality links I am primarily buying them for either direct traffic or the effect they may have on my Google rankings. So the place to start analyzing category analysis is the search results.
Some sites will rank well based on being deceptive, creative, and spammy, but those rankings will quickly change over time, and those are not the ideal sites to pattern your link profile after. It is better to look at the top ranking related sites which you believe are credible sites that deserve the position.
For example, if you are a retailer of a product, but most of the higher quality top ranked sites in your category are manufacturers, it might make sense to dress up your site and write your directory listing description to make it look more like you are a manufacturer which also sells goods directly rather than just a retailer, that way you can submit your site to a category that lists you alongside.
The co-citation you are buying when you chose a category is a large part of the value of a directory listing.
Write your site description to help reinforce your category selection. Bias it toward making your site sound relevant for the category you want to be listed in. For example, if you want to be listed as a manufacturer and are submitting to a manufacturing category make sure your description says something like manufacturer of ...
Don't put too much hype in your site description. Look at other sites listed in your category to see how they are listed. The main goal of the description is to sell the category placement, and do differentiate your site from other sites listed in your category.
Directory Category Analysis:
There are a few main criteria when considering what directory category to submit your site to.
the odds of you being rejected
the co-citation value
the global link authority of that category (ie: PageRank)
the number of listings in your category
The odds of being rejected:
The odds of your site getting rejected from a paid directory for submitting to the wrong category are going to be quite low. For a free submissions or submissions to directories ran by editors, like DMOZ, getting the category selection correct is far more important than with a paid directory.
For a paid directory you probably want to submit to the best category which is reasonably relevant to your site. If they are too liberal with category placement the directory is probably of low quality and not trusted much, but even with high quality directories usually you can fudge it a bit. And, worst come to worst, they will typically list you in the category you belong listed in even if they do not give you the placement you desire most.
The co-citation you are buying is a large part of the value you are buying when you buy a directory listing. Consider the types of sites you want to be grouped with from the above SERP analysis section.
Yahoo! paginates the directory category listings pages by popularity, so if there are over 20 listings in your category and your site is new, you may want to spend the $50 to $300 a month it costs to sponsor your category, at least until your site's popularity increases and you are one of the top 20 results in your category.
Category link authority:
Some areas of a directory are over-represented within the overall directory structure, or may be well referenced by external resources. For example, Yahoo! lists the blogs category rather high in their overall category structure. Want another example of a directory category getting a bit of overexposure?
Number of Links in Your Category:
If your category has less than 20 links then it is clear you will be listed next to the other listings. If your site is new and your category has more than 20 links then you may need to buy a category sponsorship to be featured at the top of the category to get the desirable co-citation.
Two other things to look at with the number of links in your category:
If you have a top sponsorship position in your category, or if you are bootstrapping it, and your brand is not that strong yet it may be cheaper to rank your category page than to rank your site off the start.
If your category has few links, or the other listings are not too relevant to your business, do not expect the Yahoo! Directory editors to want to list your site there.
Submitting to Other Directories?
I still think this post from April about web directories and SEO is a good primer for considering the quality of various directories, and how search engines may evaluate them.
A couple things I would add to that post:
Aged sites and/or sites with clean link profiles which are well trusted in Google are given a bit more leniency on what links may count and how many bad links they can get away with. If you have an aged trusted site you may want to dig a bit deeper for links, but for newer or untrusted sites you are best off just getting links from some of the higher quality directories.
If you are applying to become an editor at DMOZ, or other volunteer ran directories, make sure you start with a small category and sell topical passion more than you sell your commercial interests in the topic.
If you submit to a directory which allows multiple deep links with your listing, like Business.com, make sure you consider what pages will earn the most. For example, I have a 600+ page site where about 20% of the earnings come from one page. Getting your top earning pages a few more links can significantly increase their earning potential, but also note that if your deep idea is an uncompetitive niche there might be other links that you can get that will not leave such an obvious roadmap for competitors.
If your brand or core keywords could commonly be misspelled, like Client Side SEM vs Clientside SEM, you may want to submit your site to a couple average to lower quality directories with misspelled anchor text.
SEO Question: I rank #3 in Google for one of my core keywords and yet I am nowhere in it for Yahoo!. Why?
SEO Answer: Just because Google is viewed as the hardest search engine to manipulate, that does not mean that if you rank there you will also rank elsewhere. Each search engine has their own relevancy algorithm which determines how results are ordered. Over time those relevancy algorithms for each engine change, and they are never going to be the exact same at different engines.
I looked at the query and site in question, and in this instance, there was lots of link spam ranking competing sites high on Yahoo!. Those sites had 3 to 10 times as many links, and apparently Yahoo! likes garbage links a bit more than Google does, at least in this instance, at least right now.
Since many of those spammy sites were dominating Yahoo!, that meant that their rankings suppressed many garbage sites. Abhilash recently made a great post on this topic. Outside of having a ton of link equity or a killer brand, ranking across all the major search engines for certain keywords (especially in competitive areas) might be mutually exclusive.
SEO Question: I recently set up a local search site, and was wondering if it made sense to use SEO to market it?
Answer: There are many types of ideas where using SEO to market them will not make much sense. I think you probably have one of them. If you have a platform website which aggregates information and displays it in a way that adds enough value that other search engines would want to index your results then you should look into duplicate content and other related issues, to ensure you are unique enough on a per page level, but generally if you are marketing a platform which has limited content I think you are better off looking into viral marketing instead of SEO.
Ideas spread through communities. Make it easy for a certain group of people or community to share your idea / product / service / offering / etc. If you can connect with their sense of identity that is great. For example, for a local product try to hit up the local media or other sources of power.
Read and track sites and communities you want exposure from. Become part of the conversation there. See what types of ideas make the Digg home page. See what type of search sites librarians are talking about right now.
If you can talk about search in a way that is interesting to novice SEOs and yet still provide relevant search results at the same time many people will want to read what you have to say. Quintura recently got mentioned by many SEOs because they offer a search service that acts as an interesting SEO tool.
All those links from the last paragraph were announcements in the last week! If you are doing things that make people identify with you and feature you as content you don't have to buy too many ads. Google is the perfect case study for how to market a search engine.
Why SEO could potentially be useful to you:
Search is a link rich topic. Many librarians and other trusted sources freely link to search sites. If you can add enough value to make other engines want to index your pages, and can get enough high quality links, then your site should be able to get a bunch of exposure quickly. Just look at how many Technorati tag pages rank well in Google and other search engines.
You need people to care and share to build a platform:
But generally, people participate on platforms because there is some value they can get from there that they can't find elsewhere. That, and giving people a reason to talk about it, are the best ways to optimize your rankings in other engines.
SEO Question: We are considering shifting our site from offering free content to a paid only model which just offers a brief introduction into each area. How long will it take for Google and other engines to rank our site worse for changing our business model?
SEO Answer: Many sites flip from legitimate quality content sites to lead generation forms and continue to rank well for years. How long your site will survive on its current authority largely depends on
how authoritative your site and brand are,
how competitive your marketplace is, and
what business strategies competitors will use.
Just by having free content accessible early in the development of a market that can be enough to establish an insurmountable lead in a market. Look at sites like SeoToday ranking in Google in spite of not being updated in a year. But the only way that site will still outrank me a year for now is if I get banned for spamming, destroy my brand, or neglect this site. Over time markets shift, and the search results will have to shift with them if they want to be seen as credible.
If your free content gets many links then you are cutting off significant forward authority by making your site much harder to link at. Put another way, compare how often you see the Wikipedia referenced in a blog post or in the search results compared to encyclopedia Britannica or other encyclopedias that only want to give away a snippet here or there. Wikipedia beat out Britannica by allowing users to become editors and evangelists, while selling the concept of free and open.
Any long tail searches that match your current page content will no longer send traffic to your site when that page content no longer exists. You should notice that drop in traffic probably within about a month of converting your site to paid only model, but your rankings for short tail keywords may stick much longer because those are more reliant on link equity. Link equity typically dies off slowly and it will still take competitors some finite amount of time to replicate your link reputation.
Instead of moving to an entirely paid model I bet you could do better by slicing and dicing up your current content, which could help your business the following ways:
allow you to have pages and content relevant for many targeted search queries
make it less convenient to work through all of your online content (and thus make your packaged for sale information offerings seem more useful, appealing, and valuable)
the different format and slight differentiation than the content you are selling will prevent customers from feeling angry for seeing the same stuff free and paid
I don't just advocate those ideas, that is sorta what I do with this site. Who wants to read thousands of blog posts if many of them are going to be outdated? Why not just buy an up to date guide instead? Of course this model works best if you are selling an information product that covers a broad range of ideas or a field that is rapidly changing.
People are not paying for the value of your product. They are paying for their perception of value. A large amount of that perception is based on removing uncertainty by building trust with free content. Put another way, I think the value of knowing someone found and is reading an article of mine based on a recommendation is probably worth at least twenty times as much as them clicking one of my ads. If my ads cost 25 cents each then each recommended article read might be worth something like $5.00.
Another option might be to leave last year's content available online, and use it to sell current information. When search seems to be picking up more and more momentum and even MIT is giving away free course material I would be hesitant to go to a paid only model. Especially if you consider that sites with lots of content are going to be easy to identify with for many people (and thus be well read and well cited and well ranked in the search results) and what Clay Shirky wrote in Fame vs Fortune: Micropayments and Free Content:
The act of buying anything, even if the price is very small, creates what Nick Szabo calls mental transaction costs, the energy required to decide whether something is worth buying or not, regardless of price. ... The fact that digital content can be distributed for no additional cost does not explain the huge number of creative people who make their work available for free. After all, they are still investing their time without being paid back. Why?
The answer is simple: creators are not publishers, and putting the power to publish directly into their hands does not make them publishers. It makes them artists with printing presses. This matters because creative people crave attention in a way publishers do not.
Each additional user of the web is a potential link source and a potential competitor. As more artists and other passionate people enter your market some of them will compete with you, and few of them will be talking about you if you make it hard to interact with you (ie: require payment prior to them receiving any value).
By sharing content it makes it easier to learn how people may perceive your ideas prior to packaging and marketing them. In a sense, it can give you a target trusted market willing to help you improve your ideas and then help you market them.
All those links from the last paragraph were announcements in the last week! If you are doing things that make people identify with you and feature you as content you don't have to buy too many ads.
Many people who relied on one page salesletters were only successful with them because there was so little content competing for attention. In a world where more people and content are coming online each day, a paid only content business model is a quick track to irrelevancy.