It’s all over the search engine web: Google is cleaning house of Adsense arbitrage sites, which I wrote about in The Search and form a cottage industry that benefits both parties. SEW has more here. I asked Google for a statement on this and got this rather tepid, but telling response:
At Google, we are always focused on how we can make the user experience as positive as possible while still providing value to our publishers and advertisers. As part of this effort, we continually conduct automated and manual reviews of publishers and sites that violate our policies. In some cases, violations of our program policies will result in termination from AdSense.