When Facebook went public, it was already generating more than a billion dollars in revenue a quarter. When Twitter went public, it was generating well over $100 million a quarter.
There is no doubt that Snapchat is an important platform and can generate revenue - perhaps significant amounts of it - but it has a long way to go before it can justify a public market valuation anywhere near its current private market valuation.
For comparison, Twitter is currently worth about $23 billion and generated more than $400 million in revenue last quarter.
Snapchat, in its current state, might be an interesting public market investment at a few billion. Above that, there are much better risk-reward opportunities.
[1] http://recode.net/2015/05/08/snapchat-lowered-its-ad-rates-f...