It would probably look a little something like this.
Captain America (Steve Rogers)
Captain America would essentially be like your mother on Facebook; posting cringe-worthy updates and occasionally tagging in random businesses at the end of some status updates. He's trying though, bless him.
Facebook / Marvel Studios / BuzzFeed
Hawkeye (Clint Barton)
Hawkeye would launch a popular YouTube channel consisting of videos in which he does trick shots and other stuff with his bow that no one really cares about. But hey, check out those biceps.
YouTube / Marvel Studios / BuzzFeed
Hulk (Bruce Banner)
Twitter would be perfect outlet for Bruce Banner to let out his angry side. He could go on major Twitter rants without anyone batting an eye.
Twitter / Marvel Studios / BuzzFeed
Iron Man (Tony Stark)
Move over Kim Kardashian, there's a new Instagram player in town. Instagram would be the perfect place for an egotistical billionaire like Tony Stark to not-so-subtly boast about his life.
Instagram / Marvel Studios / BuzzFeed