I'm not too surprised the NBA has done this. They make some crazy rules year in and year out, though commissioner David Stern knows what he is doing (helping professional basketball become one of the top sport industries in the world). I remember last year during the NBA playoffs, ESPN would continuously report on how players would Tweet in the middle of games. From either the locker room or even on the sidelines nest to the court. NFL players also began to Tweet during games at the end of last season. It's about time they put a hold on all of this "Tweeting" and get their heads in the game. They can talk to their fans after the game is over.
Though, as a fan, I wouldn't mind knowing how my favorite NBA superstar is doing after a rough 1st period. Maybe find out why he is performing so poorly and give me a little reinsurance he will get back into the game come the second half.

As a fan I will miss the in game updates, but as a coach I would rather know he has his head in the game and not on his blackberry.