Regarding the profitability piece, they closed their mopub acquisition this week - something i believe will make or break the future of TWTR reopvenue... I believe the money is on that piece to perform or the company is dead in the water.
MoPub is the key for Twitter, I agree. It offers them a way to jump in as the leader in multi-touch/multi-device attribution, something that marketers will pay through the nose for (I know I would). I'm really interested to see what they do with it.