Entrepreneur and Napster founder Sean Parker has joined Twitter. In an amusing first tweet, Parker has apologized to Facebook co-founder and CEO Mark Zuckerberg for joining the social network — Parker, of course, is a former president of Facebook and his stake in the social network has helped him become a billionaire.

I’m not sure why Parker, who is using the Twitter handle @sparker, felt as though he needed to apologize to Zuckerberg. After all, it’s not like Zuck isn’t on Twitter himself (however, he’s far more likely to be found using Facebook).

Parker’s account has already been verified by Twitter and he has 5,243 followers at the time of this writing. I’m looking forward to seeing what nuggets of wisdom Parker shares on Twitter.