Twitter often makes more money from mobile ads than web ads

"Twitter has generated more advertising revenue from its mobile platform than from its website on many days in the last quarter, CEO Dick Costolo said Wednesday, highlighting Twitter's progress in squeezing ad dollars out of the growing number of smartphone and tablet users worldwide.
Speaking at a conference hosted by The Economist Group in San Francisco, Costolo made his remarks at a time when newly public Facebook, a competitor in the social Internet arena, faces intense pressure to improve its business performance on mobile."

Source:  Reuters, 6th June 2012