the market believes in a very high potential for growth. That just doesn't seem reasonable. It is not unreasonable to think that Facebook will expand beyond it

the market believes in a very high potential for growth. That just doesn't seem reasonable. It is not unreasonable to think that Facebook will expand beyond its current incarnation, similar to how Google is no longer just a search engine, and Amazon is no longer just an online bookstore. That's what the market seems to be saying here.