This is interesting. In a mandatory PlayStation 3 update, Sony has slipped a change to the terms of service for the PlayStation Network so that users who accept it are basically giving up the right to take part in a class-action lawsuit against them. The new clauses, termed "Binding Individual Arbitration," mandate that any Dispute Resolution Proceedings, whether in arbitration or court, will be conducted on an individual basis only.
Any outstanding class action lawsuits filed against Sony will still stand, including the class action suit filed in April over the PSN security breach. But it seems Sony is protecting itself against further litigation should it be hacked again in the future -- or perhaps if it pull another rootkit fiasco. They are in their legal right to do so, according to some analysts, but the stealthy move can't help their already tainted image in the minds of customers.
Although this could hurt consumers' chances to challenge the company in court in case of any wrongdoing, there's nothing in the terms of service preventing people from suing Sony on an individual basis.
Looking at it from another perspective, as Gamasutra notes, class action suits in the gaming world usually benefit a few (read: lawyers) while members of the class have to make do with the crumbles (i.e. The Hot Coffee class action suit against Take-Two, which netted its members a replacement game disc or from $5 to $35 in cash).
In any case, users can also opt-out of the binding arbitration and class action waiver by contacting Sony in writing within 30 days of agreeing to the new terms. The full list of changes to the agreement is available here (PDF). It's worth noting that PSN users are required to agree to the new terms upon signing in to be able to use the service.