https://phys.org/news/2018-09-facebook-twitter-pledge-defend-foreign.html

Senators had sharp words for Alphabet CEO Larry Page, who oversees Google. Sen. Marco Rubio, R-Fla., suggested the company might have bailed because it was "arrogant" while Sen. Susan Collins, R-Maine, expressed outrage over the absence.

Sandberg's appearance came several months after Facebook CEO Mark Zuckerberg testified in highly publicized Capitol Hill hearings. Like Zuckerberg, she acknowledged Facebook's lag in recognizing Russian efforts to manipulate Facebook during and after the 2016 U.S. presidential election. Sandberg detailed Facebook's efforts to fight the problem with new technologies and manpower.