From April 14th (that's this Tuesday), Blizzard Entertainment Inc. (USA) will no longer publishing the game in Europe. Pause for dramatic effect. Rather that will be done by a new European arm of the company, Blizzard S.A.S. (France). The email itself is basically a courtesy -- after all, you wouldn't actually cancel your account just for an admin change, would you?
Personally I think this a great move, it means that we, the European players of World of Warcraft, are finally being recognised as the legion we are. We're a separate territory (as should be obvious from Blizzard's European job site) and proud of it, it's just nice for it all to be official.