Searchengine Google is now monitoring visitor rates per search per clicked website.
To do this they implemented a few new techniques.
Before i expand on that, first a bit about how the internet works.
First one would go to google and type some terms, waiting for googles result page.
This page would contain links to pages.
These pages in their turn can monitor where the visitor is coming from.
But google cant see which link you click, that is vital information.
If you turn on "´site info"´ in the google toolbar, the bar requests information about the site you are viewing. you could turn this off also, off by default.
here it is, look for:
and in the links of the resultpages:
This way they can track any click going from their pages.
not with firefox though, they give you a different page with the "´onmousedown"´ stripped out.