Pricing for what? Users? That would be an unequivocal death knell. Developers? Possibly. However, it's doubtful that Twitter stands to gain any significant reve

Pricing for what? Users? That would be an unequivocal death knell. Developers? Possibly. However, it's doubtful that Twitter stands to gain any significant revenue from charging for an API. Their audience for advertising is so much larger and more lucrative, a paid API would be of trivial importance to their bottom line and a waste of time. I don't think they'll charge for anything. Doing so would relegate them to the same, minuscule potential user base as App.net has.