This was inevitable, particularly after this video surfaced. Sacramento based law firm Kershaw, Cutter & Ratinoff, LLP is investigating complaints about unauthorized charges imposed social network users who were mislead into accepting offers of dubious quality. Among those being investigated: Facebook, MySpace, Zynga, RockYou, Offerpal Media, SuperRewards and many others.

It’s ScamVille, the lawsuit. And we’ve spoken to one other law firm considering a class action claim against these companies.

Will users be vindicated and get their money back? Maybe part of it. A recent class action settlement against WebLoyalty for post transaction marketing scams led to a $10 million settlement, just a tiny fraction of the total revenue pulled in by these offers. The law firms are the ones who get a payday.

Gawker, which broke the story, makes a good point though. That video of Pincus looks bad enough on a blog. Imagine what a jury will think of it. And services like Offerpal have now admitted that what they did was questionable. This will likely settle quickly.