> What is out of the ordinary is the public markets' reaction?

But is it? Maybe the public is realizing that tweets were just a cool fad for a while. For twitter to be profitable, I am guessing, there has to be people that want to use it, and (very important) people believing that people want to use it (so they'd pay Twitter for advertising).

Compare with Google. Google provides something momre back (gmail, search, calendar, docs, photo storage, directions + many other things I forgot about).

Twitter provides 140 status messages. There is nothing wrong it, that is very cool. But I think there is a realization that it just isn't as cool as it was in 4 years ago. And it just became 3% less cool.