That being said, I'm bearish on Snapchat, at least in the short term. I don't see much opportunity for growth, not unless it manages to capture the hearts and minds of the next budding wave of teens.
Maybe I wasn't clear. From what I can tell Snap is focused on connecting people in the moment. It's more about giving people a way to share the little adventures of their day with close friends than it is about giving people a way to share a few big events in their week, or giving people a way to broadcast their lives to a mass audience of strangers (they have this functionality but de-emphasize the use case). Facebook and Instagram are more about sharing fewer but bigger moments - though they work okay for sharing more and smaller if that's what you want - they're one of the many good enough options.
I agree with your point about the next wave of teens. And I suspect that will be tricky. That said, maybe if it never catches on with the olds it'll be easier to stay popular? Maybe they can just own the teen chatting niche?