I've been playing with Google Profiles.
I was very curious that they were able to auto-connect 82 web sites to my profile. Why these 82? I own more than ten times that many web sites, and I don't own many of the web sites listed any longer.
Google claims to use social graphs to generate the my links data.
The reality though, is far more simple. Every site they listed is one that I had put into Google Webmaster Tools at one time -- even though they are not currently listed in Google Webmaster Tools.
This is damning evidence that, once you add a site to Google Webmaster Tools, Google remembers it long after you delete it.
However, I may have found a partial way out. Not every site which I ever added to GWT was listed. My guess is that sites which were later added to GWT by other owners have been removed. I can test that by creating a second GWT account and verifying some of the sites through that account. Unfortunately, I do not own some of these sites any longer, and can therefore not use that trick to remove all of the "dead" sites.
The net effect of this is that some sites which I no longer own are still on "my record" at Google. I believe that I will be far more careful about adding sites to Google Webmaster Tools in the future.