When I log into my AdSense account, I keep seeing a note from Google that I have the ability to show ads from Google-certified ad networks on my sites through my AdSense units.

Should I do this?

Google says that with more ads competing for the space, my revenue should increase.

I guess I can see this being the case on sites where there are few ads or low paying ads for the subject matter. However, on most of my sites, all of the big companies in my niche are in the ad units on my site.

I guess these companies might also advertise through the other networks, but it seems like Google would favor their own ads if this were the case.

I also wonder about the qualtiy of the ads. If a company sets a really high bid on a third party ad network, will they move to the top of my AdSense units even though they might have a terrible click through rate?

Has anyone had experience with turning on the third party ad networks through Google AdSense?

If you operated primarily in markets where there are plenty of high profile companies filling the ad units, would you bother with trying to open the ad units to more advertisers and advertisements?