Several people across the U.S. are having authentication or connection issues tonight. I haven't been able to log into my main realm for at least half an hour myself. The above screen may say I'm connected, but it's just stuck there. Sometimes it gets stuck at the character loading screen and sometimes at the authentication screen. Many readers have written in with the same problem.
According to Reythur, Blizzard technicians are investigating. From the looks of the forum posters, several internet providers across many different states are affected.
We'll let you know when we learn anything more.
Update #1: And just like that I'm in. And Blizzard states that the issues have been resolved.
Update #2: Many people are reporting that the connectivity issues have returned.