enigma1 - 1:23 pm on Apr 22, 2011 (gmt 0)
If it's indeed 20% of user interaction injected into the search engine's algo it would explain the abnormal results.
So I am guessing if your pages are "spam" you are toast.
I believe right now seems spammy pages thrive over original content.
The thing is, the lack of precaution by the end user browsing, could significantly affect search results, as you will have to add to the "user engagement" the compromised/zombie machines available worldwide. And that is a big percentage. At least from the server logs I have access to 80%-90% of visits are artificial. There are lots of new developments for ways on hijacking browsers.