I’ve given a lot of thought to Google opening up AdSense for Domains to everyone. It makes sense for Google and not a whole lot of sense for me – as an owner of domains that don’t get a ton of direct type-in traffic. If you read the material that they have written in plain English, they are clearly looking only for natural traffic – either type-in traffic, generic typos, or traffic from expired domains.
Once Google gets your domain they get all of the information about it. They immediately know that it is a parked domain, and it will immediately lose any pagerank and any possibility of being listed in Google (and probably in any search engine). If you have domains that get a lot of natural traffic, then this is not a problem. If you are hoping to generate traffic legally through SEO (or otherwise) you should stay as far away from AdSense for Domains as possible.
Most of the domains that I use to test parking companies for ParkQuick.com are listed at HealingSites.net, and it is probably obvious that these are mostly 2-word generic domains that individually don’t get an overwhelming amount of type-in traffic. In groups they do get enough traffic to compare services, and I follow some portfolios owned by others. (I also have other higher-traffic domains that I use for comparisons, but these are not listed for sale.) If I were to move groups of these domains to Google’s program I would have an uphill battle trying to develop any of them in the future and get the sites listed on Google.
After much thought I have decided to pass on AdSense for Domains for now. I would welcome others’ experiences, either as comments here or in an email to me.