When I think of Snapchat's new potential $10B valuation, I am reminded of this
signalvnoise.com
signalvnoise.com
Twitter & Facebook didn't make no money at all either for the first 3 years even, now look at them. If you have millions and millions of users that use your product all the time, you will always make money. It's just a matter of when you turn monetization on, which Snapchat is already testing with sponsored stories.
Off the top of my head:
1. Friendster
2. AltaVista
3. AOL's AIM. They tried, and failed.
I'm not saying that a huge user list is worthless, that would be silly, but until you're making money it's all just pie in the sky thinking.