Having ads should not affect your search engine placement, millions of sites would be affected if something like this was implemented.
I dont know, but I had around 4000 SERPs on MSN, and since the day I put adsense on, it goes down to 2000 SERP, what the hell?
they might prefer others though... just cuz new york times doesn't get affected doesn't say anything about the rest of us
Most of my sites have AdSense Most rank well when I search MSN But it does not seem to give me much traffic