It's fairly new, and google doesn't allow you to disclose details. So who's tried / trying it?
You're allowed to run affiliate links alongside.
There has been positive feedback that I've already seen, and the word is that it'll close down weak affiliate programs. Anyone griping about google lately might change their minds when they realize that they could be scoring highly in google's free searches and then taking money from google for displaying relevant ads.
Hmmm.... this should get interesting.