Sean Parker's a believer in social media! Parker, played by Justin Timberlake in The Social Network, advised Mark Zuckerberg and eventually became Facebook's first president used his first tweet to apologize to his former co-worker. "Sorry Zuck, I had to do it eventually. (Actually @scooterbraun made me do it.)" Scooter Braun represents another Twitter slash celebrity phenom: Justin Beiber. As of this posting Parker has 3,918 followers, but Braun's Twitter shoutout to Parker will probably give him a nice boost. And now the next time Parker tips a waitress $5,000, he'll have someplace to brag about it.