Search engines, especially Google, place a lot of trust on Global domain authority when computing their relevancy scores. If a page is on a trusted site it automatically gets a boost in relevancy scores. Premium content providers know that Google needs them so they take advantage of their market position. Lets look at a few examples of authoritative leverage in action:

• Topix is aiming to be citizen driven, but opens up new markets using an automated blogging technology called RoboBlogger.

• The Wall Street Journal, which called blogging overhyped rubbish, recently started producing advertorials. Their CollegeJournal site links to Scholarships.com sitewide, and provides a co-branded scholarship search on CollegeJournal.com.

How will Google minimize the media's ability to sell advertisements that rank in Google as though they had editorial value? They are going to have to start breaking sites and search results into pieces. If they do, it will not only minimize the downside potential of advertisements on popular sites, but that would also kill the .edu spam.

Personalization will lower the profitability of leveraging off topic broad nationwide ads by lowering their exposure by biasing search results to locally trusted sources. Matt Cutts has talked about personalization recently, not once but twice.

Given that some domainers control millions of daily page views, and there are plenty of cheap traffic sources I don't think raw usage data will be that strong of a signal of quality. Like links, usage data is easy to manipulate.

As the web gets polluted with low cost links, other low cost marketing opportunities, and recycled junk the key to Google's success is tracking attention data. They have the most popular feed reader, and their new homepage allows you to create topical tabs that show related feeds.

In tracking how people consume and share information they can understand local topical networks, while reinforcing the views of the local topical editors. It sorta creates a bunch of micro-Digglike communities, but more free-flowing, with less focus on free votes. Time is the one thing we are all limited on, and if you are paying attention to something then there is a lot of value in trusting that attention.