People can not log in at all in realms like Area 52 and Illidan.
My entire guild has been trying to get in for almost 4 hours, and we've been preparing for this for hours (we were online since 7 hours ago)
At this point Blizzard should just give people a "free" way out of this. People are BOOSTING characters on low population realms "just to level up during launch day", that is stupid to say the least - I want to play my main, and I want to play on the server I am going to progress in.