I keep getting more ads from google itself than any other.....The adsense ads are about adsense and adwords most of the time...How much do you think would be the cost per click for an ad from google itself...or do they even pay for that?
I don't know for adsense, but other companies like clicksor or AdEngage doesn't pay when filling their own ads. If you don't like that ads you can add google on your Competitive Filter.
google puts up PSA ads when there are no ads for your site/page. the ads that are about google services are ads. i have google.com in my filter,but i think they are cpm ads. if they are cpm ads and they are the only cpm ads in that zone,you can see how much they pay in advance reports.
Google has to compete for those ads, just like every other advertiser. If you filter them, there will be less competition for your ad space, and your revenue will probably drop.
It that's the case, it would be an disloyal competition because other advertisers has to pay the AdSense commission, and AdSense ads would be paying that commision to itselt.