Blizzard has just announced that you will be able to pull your Facebook friends into your Battle.net friends list. They will be testing this functionality soon in the StarCraft II beta. Since we know that the Battle.net functionality will come to WoW before Cataclysm, that means we'll be able to import our Facebook friends into our WoW friends list at that time. This is just another example of the worlds of Facebook and MMOs colliding.
Of course, the integration will be voluntary. This announcement does not mean that all those friends you have in Facebook just to increase your mafia will automatically know you are playing WoW. You will choose if you want to integrate and which friends to import.
The full PR announcement after the break.