http://www.sonyentertainmentnetwork.com ... ENT-EN.pdf
The TL;DR version
You cant sue them*, individually or in a class action lawsuit (Like the one for OtherOS thats ongoing) If you agree to use PSN you agree to this for life, even if you cancel your PSN/Other Sony service accounts
(*Them being Sony or any of its daughter/sister companies)
Makes me glad i don't use PSN, If Credit card details ever go missing again & you get billed £1000's then you can't blame Sony & insurance wont pay out as you agreed to not hold Sony liableANY 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 LEGALACTION, 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.