In recent days, social media has even doubled as a virtual debate stage, with candidates sparring in a manner inconceivable just a few election cycles ago.

Social media is driving the 2016 presidential race, as candidates of both parties increasingly view Facebook, Twitter and Instagram as key battlegrounds in the fight for the White House.

Campaigns have used social media in past elections. But in recent months, it has threatened to overtake traditional news outlets, paid advertising and the campaign stump as the top venue for candidates to rally voters, hit their rivals — and even make news.