Mark Zuckerberg testimony as it happened: Facebook CEO grilled by senators
Mark Zuckerberg is under pressure to explain how Facebook allowed the personal information of millions of its users to be scraped by a political ad firm.
Thanks for tuning into the Mark Zuckerberg Congressional Testimony Live Blog Extravaganza from NBC News!
Facebook CEO Mark Zuckerberg testified before Congress Tuesday and it lasted nearly five hours. He'll be back Wednesday for another round of questioning.
Catch up on what went down in our blog below.