Aurelie Thiele, a former MIT EECS grad student (operations research) and now a professor at Lehigh, wrote some thoughts on click fraud in response to a comment I made on one of her previous postings. In her post, she mentions something I forgot that has a bearing on Google's claims that click fraud was something "new" and not well understood. Bill Gross, who founded Overture (which bought AltaVista in 2003) in 1998, was aware of the problem even back then. (Not surprising; there had been other related incidents of fraud associated with online advertising even before that. Some kids were caught generating ad impressions on one of their sites back in 1996. I remember reading an article about it and thinking cynically that it was only a matter of time before something like this happened.) Why this wasn't brought up during the Lane's Gifts settlement is a mystery to me.