jmccormac - 9:51 am on May 28, 2012 (gmt 0)
The domain name may have been part of a Domain Tasting cycle but as there are only four registrars with two drops listed, it could be a bit more complex. Google was supposed to nuke a domain/website's PR when it dropped but with the way that domains are auctioned and traded without drops has affected that strategy.
It may have been a domain that has been traded a few times over the last 8 years or so with some PPC parking being involved as the domain switched between PPC nameservers and ordinary hoster nameservers. Without seeing the DNS history, this is only a guess.