[thebluesky]

I can't speak to the other languages, but Scala is definitely being used pretty heavily in a number of pretty major back-end systems for stock trading, cloud computing, banking and successful startups like Twitter, Foursquare, Tumblr, Quora etc.

[dasil003]

I think by "serious" the GP must have meant literally serious developers, such as those working in huge corporate body shops who are prevented from not being serious by strict regiment. Certainly management in such environs would consider authorization to use any more expressive language than Java as tantamount to handing out dynamite on Halloween.

[ExpiredLink]

I can understand that esp. young developers get bored and want to try something new and fancy. OTOH, JRuby and Groovy are, at best, niche languages without traction. The drawbacks of Scala have been discussed widely, also here on hn. Clojure? How many Hickey fans actually write real-world programs?

[thebluesky]

Many of the folks using Scala are experienced Java developers, your posts seem to be based on personal speculation rather than actual facts.