This is a nice little way for Blizzard to thank all of us for spending years in the game. With over 11 million people playing WoW, and Wrath becoming a hit overnight, there's definitely a lot of celebrating to do over at Blizzard HQ.
The little bear that you get looks a like a small version of the BlizzCon Polar Bear Mount those of us lucky enough to attend BlizzCon this year got. It's a perfect traveling companion for you as you adventure around Northrend.
Edit: The pet is active on US, EU, and Oceanic servers.
Thanks to Mangowire for sending us the pics you see below.