I was at a social apps conference a few months back and some interesting statistics were shown about Snapchat. One of the statistics was that Snapchat allows picture messages to be sent 10x faster than regular SMS. I found this fascinating because this is when I stopped looking at Snapchat as an incognito picture sharing app and more of a new, more efficient communication channel.
I don't know how Snapchat plans to monetize. It might be advertising. It might not be. But it's hard to dismiss Snapchat as being valueless when clearly millions of users are using it every single day.