I'm selling ebooks on the big 3 and have been doing well so I'm looking to expand. Have tried clickriver (so-so), kanoodle (not good for me) and ask (is looking ok). Anyone else had any positive experiences with other smaller ppc engines?
clickriver worked amazingly well for my company, but amazon is changing up their system in january so that product marketers don't get as many impressions anymore (they figured out that us advertising products on their site might actually be hurting their business!) quality of traffic was on par with the top 3 and generated the same amount of revenue this month as in yahoo for about the same cost. if you can sneak into their system still, do it... in terms of other engines, ask is very difficult to track but i wouldn't say don't use it. you just might not ever know what your return is.