Some guy from upstate NY claims that Mark sold him 50% of thefacebook.com in April of 2003. There's a few problems with that idea.
thefacebook.com was not registered until January of 2004. So we are expected to believe that Mark Zuckerburg was out there raising money for a company called thefacebook 9 months before he even bothered to register the domain name? Sorry, that is simply not believable. The first thing you do is make sure you grab the name you want.
The other issue is that if Ceglia's claims are true then the Winklevosses were totally and completely bluffing. Their claim which Facebook settled for $60 million was totally full of shit. If Mark had a single line of code written, or a single documented mention of thefacebook prior to meeting the twins in November of 2003 he could have had their claim summarily dismissed. Instead Facebook Inc litigated with these guys for five years and paid them $60 million.