We're getting news of this to you as it's developing.
I know some of you have been able to access DD online these past few days. We have just been notified that GamesSpy will shut down all their services for all games still using GameSpy.
We are looking into this right now. This will affect the PlayStation 3 version and the non-Steam PC version. This will not affect the Steam or XBLA versions of Dungeon Defenders.
Since we have just been notified, we wanted to let you all know immediately.
Here is the official word from them: http://www.poweredbygamespy.com/pricing/
We'll have more info as soon as possible.
UPDATE: Unfortunately, the PlayStation 3 and non-Steam PC versions of Dungeon Defenders will no longer have multiplayer as a result of GameSpy closing as of May 31, 2014. We are contacting Sony to make sure any information about the game clearly reflects this change. The rest of the versions will continue to operate as usual. For more information, please read this article from Game Informer.