When lawmakers asked YouTube, a unit of Google, to provide information about Russian manipulation efforts, it did not disclose how many people watched the videos on its site that were created by Russian trolls.
Facebook did not release the comments that its users made when they viewed Russian-generated content. And Twitter gave only scattered details about the Russian-controlled accounts that spread propaganda there.
The tech companies’ foot-dragging was described in a pair of reports that the Senate Intelligence Committee published on Monday, in what were the most detailed accounts to date about how Russian agents have wielded social media against Americans in