This is a great Google AdSense tip I found to improve your site revenue.
Remove MFA Sites From Google AdSense
MFA stands for Made for adsense sites. A lot of these sites are buying low cost keywords in adwords. Likely, some of these ads appear on your sites if you use Google AdSense. These type of advertisers usually pay very little per click ($0.01 to $0.05 per click). The idea is to eliminate these advertisers – low revenue for you – from showing on your site.
Here’s where I found the tip: http://www.searchengine-weblog.com/
And, here is the original source (How to details): AdsBlackList.com