Bill Venners from Artima, had the opportunity to talk to three of the Twitter developers, Steve Jenson, Alex Payne and Robey Pointer [1]. They have created and upgraded one of the fastest growing social messaging services in the world. You can learn what they think of Scala, how they use it, and understand about some of the benefits they have gained from their move.
Links:
[1] http://www.artima.com/scalazine/articles/twitter_on_scala.html