Obama's successful presidential campaigns were due in part, if not large part, to his social media savvy. More than any previous candidates, Obama harnessed the power of social media to reach young, technologically active voters. Obama's campaigns forever changed the presidential race and it is likely that future presidents will need to run successful social media campaigns.
The below figure shows the current social media presence of the 6 most prominent presidential candidates.
If we sum all twitter and Instagram followers and throw in the Facebook likes, we can get a rough estimate of social media presence. This summation finds that Trump has a commanding lead, followed by Hillary and Carson.