Mark Zuckerberg is willing to testify to Congress, isn’t sure if the Russians have your data. And, he’s sorry. Mark Zuckerberg is willing to testify to Congress, isn’t sure if the Russians have your data. And, he’s sorry.USA TODAY The Latest: Cambridge Analytica whistleblower regrets workWashington Post Revealed: 50 million Facebook profiles harvested for Cambridge Analytica in major data breachThe Guardian Full coverage