The fly in the ointment was that Twitter's monthly active users increased just 14 million in Q1 to 255 million total — not the sort of big growth investors were looking for to prove that Twitter is becoming a truly mainstream platform.

Still, fretting over the company's user growth obscures the fact that Twitter has been extremely savvy about squeezing revenues out of the users it does have. Twitter has quietly built a $100 million-a-year data licensing business from its user information, and Twitter CEO Dick Costolo says its recently acquired mobile ad network, MoPub, now reaches 1 billion users.