Scala also hits the sweet spot of both new but usable in production. Linkedin, Foursquare, and Twitter all have significant portions of their apps written in S

Scala also hits the sweet spot of both new but usable in production. Linkedin, Foursquare, and Twitter all have significant portions of their apps written in Scala. I'd be a little more hesitant about creating a production app with Haskell, though it's been done.