It's not Barack Obama.
He was called the "Social Media President," as the first one to really have engaged with an online audience. Some even claim he was too good at it. That his legacy will just be the "cool dad presidency."
I believe Obama won't be remembered as the real first social media president. Neither will be Donald Trump. Sure, the latter is using Twitter as a powerful (and dangerous) tool to undermine media organizations. In my opinion, that's not social media, that's broadcasting.
We already saw it with Trump: In the age of social media, the persons seem to become more important than the political party and experience. With social opening the doors for more people to attract an audience, it could also change the political landscape.
This is why I believe there will be a new wave of social media presidents. Someone who wouldn't be known without social media. Maybe someone we're currently calling "influencer." Someone who can appeal to millennials, which the current candidates clearly struggled with.
The first real social media president might even be this dude: