One of BlackBerry's features is BBM, a private IM network for BlackBerry owners. People love it because it's counted as part of your (fixed price) BlackBerry mail, so there's no extra charge like SMS or a conventional data connection. Apple and Google don't have anything comparable. Sure there's Google Talk but anyone can use that, there's no exclusivity.
The buzz I meant was media buzz. Among users, I think Blackberry has plenty. Their users are fanatical. (Stephen Fry had an article on this a bit back, as I recall.)