The blockbuster hearing was forced to recess for several minutes while the committee tried to "make contact" with Zuckerberg.
"We are unable to make contact with Mark Zuckerberg," said Senate Commerce Committee Chairman Roger Wicker. "We are told by Facebook staff that he is alone and attempting to connect with this hearing."
"This is a most interesting development," Wicker said. "We're going to accommodate the request of the Facebook employees."
Zuckerberg did get back online soon enough, though.