I rarely like to report on things that advertisers cannot control, but this story is kind of crazy. A recently reported malware strain infects computers without them having to download or accept any requests – the infection results just from visiting another infected site. This is not necessarily new, but what it does is sort of novel.  When the infected user runs a search, and clicks and ad, they are sent to other pages, and potentially shown other ads. It’s a bit complicated, but the traffic and clicks look like legit clicks in the eyes of the search engines, so they are harder to detect. I would hypothesize that the better (bigger) search engines (such as Google), have pretty good engines for trapping this type of fraud but that the smaller ad networks do not. This is another reason why I tend to recommend advertisers avoid smaller networks outside of Yahoo, MSN and Google.

Here’s the full story: 

http://www.mediapost.com/publications/?fa=Articles.showArticle&art_aid=151750&nid=127508#