Let say I am using a Pay Per Lead offer and use Yahoo + Google to advertise it. I create a landing page with a link to the affiliate page. I set my destination link for my yahoo like so mylandingpage.com/?ID=yahoo and google mylandingpage.com/?ID=google. When a visitor click on that ad and go to my landing page, go to affiliate page and completed the offer/survey, do the tracking ID for the traffic source go into my conversion report as well? I don't think it does because after the visitor went to my landing page the ID=yahoo/google doesn't store into next link queries.
the only way for you to track back to your google or yahoo account would be to ask them merchant to add your tracking pixel to their thank you page. Some merchants will do this and some will not.