A fascinating blog post from a fascinating outfit, Click Forensics.

“When an infected user clicks on one of these sponsored links, they always seem to end up on the correct destination domain (so clicking a sponsored link for Dell.com, for example, will always take an infected user to dell.com). However, due to the DNS poisoning, a click on a sponsored link will never go through Google’s own click-counting redirect. Google never sees, and therefore never charges for, that click. The advertiser gets a free click, instead of a paid one, and Google loses the revenue. The Bahama Botnet strikes again.”