"For our algorithms, ads generally don't play a big role."--John Mueller, Google (http://www.seroundtable.com/ads-google-algorithms-13110.html)
Webmasters don't have much control over Vibrant's ads. It's not possible to abuse them the way it is with Adsense. You can't position them above the fold or spam a web page. Vibrant controls where they are seen and how many are viewable. They are careful and generally don't cause a bad user experience.