"There's some very subtle clickthrough tracking going on at Google. Just before you click on a link on a search-results page, at the 'on mousedown' event, Google rewrites the links in its search results with a long redirector URL that is presumably being used to track which search results are being selected most often."
Monday, August 22, 2005
Boing Boing: Google stealthily monitoring clickthroughs from search-results
