I haven't consulted any lawyers about this, but basically I have no interest in any of your personal information, nor will I ever sell it or give it to anyone (with the usual law-enforcementt disclaimer). The only reason I even ask for it is because I want to keep some control over who gets to edit the site. Unlike, say, Wikipedia, I don't anticipate having millions of fanatics checking every page every few minutes to keep vandals at bay, so in order to prevent any old idiot from coming to the site and messing it up, I ask for you to register before you can edit.
That's it. Hope you don't mind. Personally I'm suspicious of registering and hardly ever do it -- I get enough spam as it is. But I won't misuse your info -- I promise.