Does how much money you make matter? Some people keep score of their success in terms of dollars, but I still prefer to measure how I am doing in links over money because I think that having a large reach and fast feedback loop will lead to more learning, opportunity, and economic stability than just having a chunk of cash in hand.
The amount of cash you can make from a market is largely dependant on the size of a market and how scalable your business model is. Search works with just about everything and is pretty damn automated. And thus Google is worth about as much as Yahoo!, eBay, Amazon.com, Ford, and GM combined. I have a site about academic stuff that is comfortably over $100 eCPM. I have another site in a different niche in that vertical and the site makes next to nothing for the traffic it has, sporting a completely worthless $15 eCPM. SEO Book does decently well on the financial front (especially because it leads to a ton of indirect revenue streams), but most people do not want to learn SEO. Beginners to the market prefer a tool that provides some alleged secret advantage and established people think they know everything already. For as aggressively as I market this site, how much time I spend on it, and its level of market saturation the site makes nowhere near as much as some of my other projects. I partner in other ideas that have far more potential because they are far easier to scale and/or are in markets that are much larger in nature.
Some people looked at the $132,000 AdSense check that Shoemoney posted a picture of and asked how is that even possible. The thing is, for as well as he is doing there are still others that are even doing way better. In a few years he will probably be making way more than he is today. After you get beyond self sustaining it is all just an issue of scalability, market value, and market depth. And testing and tracking of course, if you are seriously scaling things out.
When I saw Shoemoney post that check I believed it was true because I have seen pieces of so many markets and kinda understand the whole scalability concept. I also have made thousands of dollars by accidentally misspelling a casino name. Some markets just have a boatload of money in them.
I chat with Jeremy from time to time, and one day he decided to show me how easy it was to make money from ringtones. I gave him my AdCenter login and $5,000 to play with. He let me pick a domain name out of a small list. I thought KingOfRingtones.com sounded the spammiest, and thus chose it. :)
He guaranteed that I would make money and said he would reimburse click cost and split the profits in half. In the month the test was active the spend was $1,500 and at the end of the month I got a check for $4,721.60.
Of course the value was not in the cheesy landing page, but in the ~ 200K keywords he uploaded to the account. It takes some serious resources to gather that much market data, but if you can create a way to gather relevant search queries and bid on them before the competition saturates your market you can make great profits. Having unique data sources is like having great link authority. It provides you a business advantage that is hard to replicate and highly profitable in high value verticals.