Blizzard has confirmed to us that all of these accounts belong to the individuals associated with them and are not fakes (and that they are all OK with being posted publicly). Further, what these employees say on Twitter is not endorsed by Blizzard. Sometimes they might talk about things related to WoW, while other times it could be something completely unrelated.
Please also be respectful of these people's accounts. Don't pepper them asking for invites to a beta, and so on. It's not going to happen, and no one likes to be bugged about such things.
That said, follow away and enjoy some nice insight into @ChrisMetzen's WoW playing. The full list after the break.