Goodbye PSN, Hello SEN
As of today, users with a PSN account no longer have one, but instead have a SEN account. This is a name change that Sony has agreed to to help them connect users to Sony rather then just a Playstation.
February 7th is the day that any user who signs on the Playstation Network will be required accept the new terms of service, user agreement, and privacy policies in order to sign on to the Playstation Network. A name change or password change is not required. One change to the new policy makes you finalize any pre-orders placed through PSN, which means pre-orders cannot be refunded:
"You may not cancel a preorder at any time, and refunds are not available for preorders, subject to applicable laws."
​Sony's statement also includes "This helps us get closer to our goal of establishing a global comprehensive network platform of services across games, movies, music, and more."
Source:
http://www.gamespot.com/news/psn-accounts-getting-a-name-change-6349822
