They concluded that there was a significant Russian effort to interfere in general, and to stoke racial division in particular.
The report details how a Russian troll farm called the Internet Research Agency used automated posts and fake social media identities to hurt Hillary Clinton. Their research uncovered the fact that about 2/3 of their Facebook posts were focused on race, and that they inundated potential black voters with messages like these: “Don’t Vote for Hillary Clinton,” “Don’t Vote At All,” “Why Would We Be Voting,” “Our Votes Don’t Matter,” and “A Vote for Jill Stein is Not a Wasted Vote.”
The conclusion of the committee was that the giants of social media can’t be trusted to police themselves, and that some additional government oversight is essential.