At 300 million active users (exact numbers debated), if even 1% paid $10 a month for promoted Tweets, that's 30 million a month. That's not pennies. King Games and Supercell (Clash of Clans), have shown that microtransactions are a profitable enterprise when you abuse human reward systems. What better reward to abuse than attention?

> That's not pennies.

To Twitter's shareholders, yes it is. You can make that much with just a few large marketing deals, that's their end game.