martinibuster - 3:17 pm on Mar 8, 2013 (gmt 0)
Ordinarily I considered the 336x280 ad units a tad big and even aggressive. But somehow they don't look that way as implemented on this site. Here's what Google AdSense Support recommends: [support.google.com]
As a rule of thumb, wider ad sizes tend to outperform their taller counterparts, due to their reader-friendly format. Readers absorb information in "thought units," several words at a time. Wider sizes let them comfortably read more text at a glance without having to skip a line and return to the left margin every few words, as they'd have to with a narrower ad.
If positioned well, wide ad sizes can increase your earnings significantly. The sizes we've found to be the most effective are the 336x280 Large Rectangle, the 300x250 Medium Rectangle, the 728x90 Leaderboard, and the 160x600 Wide Skyscraper.
Anyone else use the large rectangles?