Who benefits from Twitter? Social media and political competition in the U.S. House of Representatives

•Evidence about the potential impact of social media on campaign financing.•The association between politicians' social media activity and their fundraising.•Information technology, campaign finance, and political inequality.

Many researchers have assumed that social media will reduce inequalities between elite politicians and those outside the political mainstream and that it will thus benefit democracy, as it circumvents the traditional media that focus too much on a few elite politicians. I test this assumption by investigating the association between U.S. Representatives using Twitter and their fundraising. Evidence suggests that (1) politicians' adoptions of social media have yielded increased donations from outside their constituencies but little from within their own constituencies; (2) politicians with extreme ideologies tend to benefit more from their social media adoptions; and (3) the political use of social media may yield a more unequal distribution of financial resources among candidates. Finally, I discuss the implications of these findings for political equality, polarization, and democracy.