Class actions are not about rounding up plaintiffs so you can shakedown BigCorp. That's only what enterprising American lawyers have made them. And that's what the public sees. Class actions are supposed to be about jusdicial efficiency. If enough plaintiffs all file suits with the same claims in the same court against BigCorp, the court is going likely to refuse to hear each one individually. Too much work. Courts are staffed by people who are lazy just like you and me. In nerd speak, developers do not keep answering the same questions again and again. They create FAQ's. The court will be more receptive to all these repetitive suits against BigCorp if the suits are filed as one: a class action. The court hears one case, and reduces its workload.
Given that we now have the means to easily coordinate group action via internet, e.g. group buying, crowd sourcing, etc., what's to stop people from coordinating group litigation. If enough people invidually file suits against Facebook with the same court, it leaves that court little choice but to encourage a class action. Companies like Microsoft can make you agree not to join a class action, but they can't stop you from filing a suit on your own for any and every claim. And if enough customers file the same suit in the same court, a class action may well be the result, even though the customers never sought to join one. And that's because class actions are not about shaking down BigCorp by rounding up plaintiffs. They are about reducing the workload of the court and the expense of hearing numerous suits all with the same claims and facts.
If a large contigent of Facebook users all resolved to sue Facebook at the same time in the same jurisdiction, _individually_, the results could be very interesting.