I'm gonna bump this for more responses.
Today I loaded a page on my site on which the ONLY ad was from adult adworld.  
Spysweeper popped up with an alert about "focusin.ad.targetnet.com" which was installing a cookie.  I Googled for that term and found this: 
http://research.sunbelt-software.com...threatid=71456
This is it for me. Googbye Adult Adworld.