This has been discussed before, but I wrote a little article about it on my proxy blog!

Here is a sneaky preview on the article:

There is something all proxy owners should now… Google Adsense, the biggest proxy monetizer is currently banning a lot of proxy owners who use the same content on all of their proxies...

Read more here: ProxLists.Com Weblog :: Google Adsense :: Beware Proxy Owners!