Comment Re:Only if you put the data there to begin with... (Score 2, Informative) 152
Even if you've never used the Address Book app this information could be in there. In the OS X first-launch setup dialog it asks for your real name, and that gets automatically inserted into the address book. I'd wager that most people who use Macs have done this, so their real names are accessible to any website using this technique.
Additionally, though this is less likely, if you fill out the registration form during setup I believe that information also goes into the address book, so there's your home address and email too.