StumbleUpon Ads on Digg : the relax game of rivals?

Yesterday morning, Pete Cashmore on Mashable wrote an article bout this game named “StumbleUpon Ads on Digg“. Last year, I wrote an article bout Gocnhin.com & Thethaovanhoa Online named “Buôn có bạn, bán có phường” (an Vietnamese idiom meant “Do biz in a basket” – copyright by TaiTran)  to wonder why two rivals (of online news) can advertise for each other.

Back to  Digg, tks Michael Pinto for this pix above. The funny thing here is Digg “allows” StumbleUpon to place an banner bout StumbleUpon Advertising. Pete said in his article that Digg need to filter rival ads. But I think that maybe you can’t deny this trend (advertise for your rival). Adapt it if you can.