The PlayStation Network has been down since Wednesday, for what seems like some unscheduled maintenance work. However, it now turned out that the PSN was hacked so Sony took measures to protect the network by shutting it down to investigate the intrusion. Sony has today released an official statement about the downtime.
An external intrusion on our system has affected our PlayStation Network and Qriocity services. In order to conduct a thorough investigation and to verify the smooth and secure operation of our network services going forward, we turned off PlayStation Network & Qriocity services on the evening of Wednesday, April 20th. Providing quality entertainment services to our customers and partners is our utmost priority. We are doing all we can to resolve this situation quickly, and we once again thank you for your patience. We will continue to update you promptly as we have additional information to share.