“I think the reason Twitter matters is, it’s the place where a very self-selected slice of extremely politically active, politically motivated people go,” said Aaron Smith, director of Data Labs at Pew Research Center.

10% of U.S. adults on Twitter produce 90% of the tweets, he said. Twitter users skew to college-educated vs. non-college users. They also skew Democratic.

Of 30 members in Congress with more than 1 million followers, Smith said that of his last count, 20 were Democrats and 10 Republicans.

And the 10% of U.S. lawmakers with the largest number of followers were getting 84% of the favorites and 81% of retweets that go to Congress collectively.