The new PlayStation Network Terms of Service seems aimed at preventing class action lawsuits from occurring in the future. The TOS specifically says that by agreeing to it, you agree to settle any legal disputes with Sony individually, instead of as a class action. While most of the document is the standard legalese you've come to expect from a TOS agreement, it's a portion of section 15 that is catching attention:
ANY DISPUTE RESOLUTION PROCEEDINGS, WHETHER IN ARBITRATION OR COURT, WILL BE CONDUCTED ONLY ON AN INDIVIDUAL BASIS AND NOT IN A CLASS OR REPRESENTATIVE ACTION OR AS A NAMED OR UNNAMED MEMBER IN A CLASS, CONSOLIDATED, REPRESENTATIVE OR PRIVATE ATTORNEY GENERAL ACTION, UNLESS BOTH YOU AND THE SONY ENTITY WITH WHICH YOU HAVE A DISPUTE SPECIFICALLY AGREE TO DO SO IN WRITING FOLLOWING INITIATION OF THE ARBITRATION. THIS PROVISION DOES NOT PRECLUDE YOUR PARTICIPATION AS A MEMBER IN A CLASS ACTION FILED ON OR BEFORE AUGUST 20, 2011.
The full document (via GameSpot) covers the Sony Entertainment Network and PlayStation Network. There does seem to be a way to agree and still retain your class action rights, however. Kotaku reports that the agreement also includes an opt-out of the class action waiver, if you send Sony written notice within 30 days of accepting the agreement. The notice needs to include your name, address, PSN name, and a clear indication that you don't wish to resolve disputes through arbitration. Plus, you need to send it the old-fashioned way, with an actual letter. Yes, those still exist.
The new TOS won't impact any suits brought before August 20, 2011, so the ones still pending like those that followed the PlayStation Network breach would be unaffected. However, like any large company Sony has a history of these suits, and this is certainly a move to prevent further ones.