You may have noticed on the WoW login screen that Blizzard performed restarts this morning on all servers.
We will be performing restarts on all US realms on Thursday, November 27, beginning at 5:00am PST and all Oceanic realms at 12:00pm PST (7:00am AEST, November 28). Each realm will be down for approximately 15 minutes and the overall process last about 1 hour.
According to Zarhym, this was to address a bug in Wintergrasp that was allowing one faction to dominate the other (free experience bonus, honor, shards, etc.). The PvP zone should be acting normally now.