(UPDATE: We clearly got way too excited about this- it's evidently been around for a while, but may have just become active today for us here at Tweak Town. )
It's true. The social network notorious for hoarding user data just opened up its vaults. You will now find the following option in your Facebook account settings:
Anti-Facebook and open-web advocates have been decrying the site's miserly approach to user data for years. The ill-fledged Diaspora open-source Facebook clone even launched on that very premise. Users can now leave, well, anytime they want, with all of their data in tow. I doubt that this changes Facebook's policy on retaining your data after you deactivate your account "for your convenience", but it's definitely a step forward.