Updates were being posted on the Datagram website (www.datagram.com) but now something has changed. 5 minutes ago there was a message about them being back up and running but needed to setup their backup systems and rebuild.
Now a new webpage is being displayed. Just checked and still getting the Authenticating... message on GE.
The only thing I can say is that it does look like they continue to make progress and do have power back. The question is, is what do they need to get the Activision servers back online. Could be 5 minutes or 24 hours from now.
I recommend you follow the Activision and Datagram Twitter feeds for the lastest:
Activision Twitter Feed: https://twitter.com/ATVIAssist
Datagram Twitter Feed: https://twitter.com/DatagramNYC