Moments ago this conversation took place via SMS to my Google Voice number:
(408) 642-XXXX: My bad bt wat u doen 2:47 PM
Me: Who is this? 3:16 PM
(408) 642-XXXX: Wh0 iS dIS 3:16 PM
Me: Yes, that's what I asked. Who is this? 3:17 PM
(408) 642-XXXX: N0 N0 WH0 iS dISz 3:18 PM
Today I received my Google Voice invite. Do you remember when Gmail was invite-only? It's like that, for now. You can read about the features here. However, unlike Gmail, account owners don't have the ability to send invites of their own (yet?).
So what is so special about Google Voice?