Facebook Vows to Sacrifice Growth for Secure Operations

Facebook Inc. extended its dominance in online advertising in the third quarter but said it would sacrifice some future growth to invest more heavily in its safety and security operations to address the growing scrutiny of its power and influence.

The social-media giant reported a 79% jump in third-quarter profit on Wednesday, the same day lawmakers grilled executives from Facebook, Twitter Inc. and Alphabet Inc.’s Google during congressional hearings that focused on alleged Russian propagandists’ activity during the election....