as a threat to FB it worth much more. FB is just too slow to recognize it. Wrt. feeling of immediacy/in-the-moment/real-time we have progression from "archaic grand-ma long form" style of FB status update, wall posting, etc.. -> TWTR -> Snapchat. FB is $100/user, TWTR is $100/user and the $3bn is about the same valuation for Snapchat.
The real question is how in the world any of these companies are going to making $100/user. I am a user of FB and TWTR and I can't imagine how I will ever make that much money for them. Certainly I can see some money, but not that much. CPM's just aren't that high. Snapchat? not a chance.