Candidates in the 2016 U.S. presidential election use more social networks than politicians of the past, in hopes of tapping the millennial market. In the past, Obama heavily relied on social media to win the previous two Presidential Elections. See POTUS 2016 for more.
Personally, I think Google itself can swing the election. It’s crazy, but our votes ultimately don’t matter all that much in the Presential Election. It’s up to the Electoral College, whoever they are.