Didn’t the Playstation Network go down for maintenance just a few weeks ago? Regardless, Sony is once again shutting down the service to spruce it up, or whatever they do when they pull it down.
Starting March 1 at 11am ET, the PlayStation Store, account management and PlayStation Home will be unavailable. The service is scheduled to come back online at 2am ET the next day. The maintenance will affect the PC Playstation Store as well. For more details, check out the Playstation community blog post.