On February 7th, the Playstation Network will be going under a cosmetic overhaul. The Playstation Network is being renamed to Sony Entertainment Network. Sony cites that it will easier for users to associate the Sony Playstation brand with all of the Sony's products. The name change will not affect current PSN account holders other than the "PSN" part.
"The rebranding of PlayStation Network accounts to Sony Entertainment Network accounts is a change in name only," explained Sony in an email to Eurogamer. "Your username or password will not change, nor are we asking you to change them."
Sony will be issuing a new Terms of Service and User Agreement along with the name change from PSN to SEN. Declining the new terms much like any user agreement means you will not be able to access your SEN account.