http://blog.us.playstation.com/2014/12/27/playstation-network-update-3/#sf6590558
PlayStation Network Update
Posted by Catherine Jensen on Dec 27, 2014 // VP, SCEA Consumer Experience
The video game industry has been experiencing high levels of traffic designed to disrupt connectivity and online gameplay. Multiple networks, including PSN, have been affected over the last 48 hours. PSN engineers are working hard to restore full network access and online gameplay as quickly as possible.
From time to time there may be disruptions in service due to surges in traffic, but our engineers will be working to restore service as quickly as possible.
If you received a PlayStation console over the holidays and have been unable to log onto the network, know that this problem is temporary and is not caused by your game console. We’ll continue to keep you posted on Twitter at @AskPlayStation and we’ll update this post once the problems subside.
Thanks again for your patience.