Senate Dem wants tech firms to notify users exposed to Russian propaganda

Sen. Richard Blumenthal (D-Conn.), next to a poster of an online ad designed to suppress Clinton's vote (AP's Andrew Harnik)

Democratic Sen. Richard Blumenthal today asked Twitter, Google and Facebook to inform all of their users who were exposed to ads and content purchased or placed by Russian actors during the 2016 election.

"You owe your users full information regarding when, where, and how they may have been unwitting participants in Russia's campaign to sow division and spread disinformation in the United States," Blumenthal wrote in letters to the companies' CEOs.