As much ink was spilled about competitors' failures, it's interesting that this won't be available some until vague window next year, and needs to be tethered to an iPhone. The interface looks interesting. The ridiculous draw pictures to each other bit, though -- what a gimmick.
How do you know? I couldn't find that on Apple's iWatch page. (Not doubting it, everyone is saying it, but I'm just wondering where it is or if it's just an assumption.)