Google contacted many publishers by email this week announcing an upcoming change in how AdSense ads work. Right now the entire AdSense ad is clickable, including the background. Starting this Friday (?), only the title and URL will be clickable. This is supposedly to decrease "accidental clicks". This will probably result in a lower CTR for almost all publishers, but it will result in a better ROI for the advertisers and thus hopefully higher bids (or at least that's google's spin on it).
Here's the old and new:

I'm still up in the air on this. I'm not real happy with google right now because they've rolled out a TON of changes recently and some have been ok, but most have really just made my life difficult.
The only plus I see to this is advertisers may start using the content network more and thus increase bids in the auction. I'm not sure how many clicks on my account are "accidental" but I guess we'll know soon.