martinibuster - 10:27 am on Jun 10, 2013 (gmt 0)
We’ve already updated this for our 300x600 and 970x90 ad units and now we’ve extended this flexibility to our 336x280 ad unit, allowing it to serve a 300x250 ad when doing so will maximize the performance of that ad unit for the publisher.
With this change you may now occasionally see a 300x250 ad served in your 336x280 ad unit when that unit is opted in to showing image ads. 300x250 and 336x280 image ads will both compete for your 336x280 ad unit with the most competitive ad served thus maximizing the earnings on your ad unit. When a 300x250 image is served it will be centered in the 336x280 ad unit...
Increased competition, in theory, means increased earnings.