I have two questions: Is the whole ad box clickable similar to how Adsense use to work before the recent changes? Does having Yahoo ads in a domain seem to bring in more Yahoo traffic and in effect raise you in the Yahoo SERP?
Yes the whole ad is clickable as Forgotten said. For your second question no it doesn't help with SERPs.
never try yahoo ads b4....btw, i think they have small appearance as well as majority are using Google.........