Great Gaming Crusade: "The PlayStation Network is, once again, down.
We aren’t totally sure if this is a maintenance issue, hack or some other situation, but we are looking into it. An error code of 80710016 is given with a message of “An error has occurred. You have been signed out of PlayStation Network.” It doesn’t specifically give the undergoing maintenance message, but it still very well could be that."
Updated: Most users now report that the PSN is back up. Also, a new link shows that this was an intended maintenance issue even though that page cannot be found online by searching. The message and time frame given also do not match what the Official Sony page says.