Where does this data come from? Google explains it comes from “aggregated Google Toolbar data from users who have opted in to enhanced features, publisher opt-in anonymous Google Analytics data, opt-in external consumer panel data, and other third-party market research. The data is aggregated over millions of users and powered by computer algorithms.”
via Google Lists Top 1,000 Sites On The Web & Then Lets You Advertise On Them.
This is mighty powerful and the fact that Google has the ability to do incredible things with all that data scares the heck out of me.
