After ban, Twitter ad firms put on brave face

When Twitter dropped the hammer this week on third-party services that place ads into users' "tweet streams," you'd think it would have come as terrible news to those very services, right? Not so! In fact, four such companies have already insisted their futures remain bright. Their hopes hinge on Twitter's definition of "inject[ing] paid tweets into a timeline," which seems to allow paid tweets as long as they aren't dropped in automatically through the Twitter API.