Data protection activists challenging Facebook in a Vienna court said on Wednesday they had closed the list of plaintiffs after 25,000 people joined a campaign alleging that the social media giant had violated users privacy. We hoped for broad support, but the number … has exceeded my most optimistic expectations, said Austrian law student Max Schrems, who launched his class action only last Thursday. Schrems, 26, has enlisted the public to help him take on Facebook, a U.S.-listed company worth $189 billion with 1.32 billion users across the globe. Schrems said he had closed the list of plaintiffs because his legal team needed to verify and administer each claim that Facebook users submitted.