How are the 3 stars selected in an NHL game?

I'm a Pens fan, and was obviously excited about the win over the Caps. Win I saw the three stars for the game I was pleased. 3rd star: S. Crosby, 2nd star: A. Ovechkin, and 1st star E. Malkin. I would of liked to see Sid 2nd or 1st, but Ovechkin is great and is always deserving of what he earns. Then I went onto NHL.com, and saw Sid as the 3rd star of the day. I'm not complaining, but how is this possible when he wasn't even 1st star of his game? Who picks the stars for both the games, and the NHL.com site?