When you try to export your address book a note pops up: "Hold on a second. Are you super sure you want to import your contact information for your friends into a service that won’t let you get it out?"
That's harsh -- especially from a behemoth that believes in transparency ... until it doesn't. (Care to share that algorithm, Sergy?)
So, you can download your own data from Facebook, but you can't download friends, for instance. It's called the 'social graph' and they're pretty fierce about protecting it. Google's open approach is pretty much polar opposite to FB. And their 'Me' social networking solution will reflect that stance.
Two enter; one shall leave.