If you’re a developer and keen to take advantage of the newly updated Open Graph, then your should check out the Facebook Developer’s site. While the keynote is still going, the dev site has already been updated.
Open graph will also support ratings. This means that application interactions posted to user’s walls, will provide analytics back to developers about what is most engaging and most annoying. This information can inform future development decisions.
Those who aren’t developers may also want to check out the site, as it contains a lot of information and images about today’s F8 announcements.
More info @ https://developers.facebook.com/docs/beta/