Here's former Microsoft CEO Steve Ballmer's first tweets on Twitter tonight. And if this is authentic, then he's got some explaining to do. Why is he tweeting from an iPhone?

Thanks for having me @Twitter! Guess I'm supposed to start with a #selfie, right? pic.twitter.com/Ivcas8gn2T

— Steve Ballmer (@MicrosoftSteve) April 18, 2014