Increase you Google AdSense revenue, update

Some time ago I promised to publish results of my experiment. So, can you increase your Google AdSense revenue by using Competitive Ad Filter?

The answer is not so clear. At least in my case. I was comparing results from last 2 months to those, when I was not using Competitive Ad Filter. I think that 2 months is big enough to provide statistically valid data. For those 2 months my average CPC (Cost Per Click) increased by 20%. I'm sure that it is possible to achieve better results by further optimising filtered sites. At the same moment results for 1 of  my sites were negative. And 2 others showed better than 20% rise (compensation for site with negative results). Google send optimisation report saying 'After an automatic review of your sites, we think you might be able to improve your monetization using the following tips:You may be filtering ads that monetize well on your site.'

Their solution for optimisation was:

Keep your filter list small

Is your account filter list working a little too well? Consider reducing the number of filtered ads. While filtering is a quick and easy way to prevent unwanted ads from being displayed, keep in mind that filtering decreases the number of ads that can appear, thereby decreasing your potential earnings as well. In order to increase the variety of ads served to your pages and to make the most of every opportunity for additional revenue, try removing URLs from your filter list. Also, instead of filtering out the top-level domain of an ad (which will prevent any ad from that domain from appearing), filter just the exact destination URL.

This makes me feel that more work should be done and http://www.adsblacklist.com is a good place to start.