WHOIS and Backlinks: Think of this this way. More and more registrar are providing privacy option on the whois as identity theft if a big thing these days. More and more people are using the whois privacy. Does that mean all there changes will impact their backlinks or PR? I don't think so. Like sweetfunny said you are simply unlucky to have lost the backlinks.
I'll give you 100's of concrete examples. First one that springs to mind, http://www.the-ffu.com Search the domains section, it's still PR4 and the Whois info and domain changed hands at least 3 times and it went through the last PR update without the PR changing. More domain bought it off someone, i bought it off him and i sold it to someone else. There's 4 Whois changes. Also, http://www.xenosys.net Same deal, changed hands at least 3 times and went through the last update without dropping. Actually i owned it during the PR update and it was a blank page at the time. Search the domain forum to confirm. Trust me, after buying/owning/selling 1,000s of Pagerank domains since the first ever public toolbar export i know what i'm talking about. Edit: Check on domain Tools, you will see 5 Whois/Registrar changes for the first example and so on. http://whois.domaintools.com/the-ffu.com
Does it mean if the domain has strong backlinks, but I do nothing to it, only a default page by your registrar, the PR will still stay?
so it's good to buy dropped domain then. i was considering about it maybe i should try to buy and develop it to prove this hypothesis myself.