breeks - 9:16 pm on Apr 30, 2013 (gmt 0)
Everyone once in awhile I get a message to add this or change that from AdSense, most of the time they get ignored.
Took them up on one suggestion and the results have been a substantial increase in earnings from the same ad position, 3X better.
Same position just different ad size opted in for image and text.
So if you have any of those messages you might want to give them a try.
I have a couple of more messages to check out and do some more testing.
According to the Adsense blog
we will only contact you if we expect you'll see a significant benefit from making the recommended changes
and they were right.