http://www.washingtonpost.com/blogs/the-switch/wp/2017/10/31/facebook-google-and-twitter-are-set-to-testify-on-capitol-hill-heres-what-to-expect/

Top officials from Facebook, Google and Twitter will testify on Capitol Hill Tuesday afternoon, igniting a charged week in Washington where lawmakers across three committees will press for an explanation of how misinformation during the 2016 election was used on the largest and most influential Internet platforms in the country.

Tuesday's hearing by a Senate judiciary subcommittee, comes a day after the prepared testimonies of Facebook and Twitter revealed that the reach of the Russian-connected misinformation campaign on their platforms was much larger than they had initially reported. As many as 126 million Facebook users may have seen content produced and circulated by Russian operatives. Twitter discovered that 2,752 accounts were controlled by Russians, and more than 36,000 bots tweeted 1.4 million times during the election. And Google disclosed for the first time that it had found 1,108 videos with 43 hours of content related to the Russian effort on YouTube. It also found $4,700 worth of Russian search and display ads.