No clear way of monetizing? They are grossing more than a billion on 300 million users. Seems like they are quite capable of monetizing.
I use Twitter daily, and would hate to see it disappear. But how much of current revenues are a product of companies still "experimenting" with the Twitter ad ecosystem? What happens if those channels provide less ROI than everyone expects? That's the way the trends appear to be heading.
Twitter's 'cost per impression' is much higher than Facebook's...might not make it as attractive to advertisers.
If Twitters CPM is much higher than Facebook's it's because it is attractive to advertisers. Otherwise they wouldn't charge as much as they do. (unless there's something else going on, which seems doubtful in this case)
Not necessarily. It may simply be overpriced but not yet at the point where the market has enough information to force a correction.