[Shameless plug] I also created https://github.com/lucianghinda/programming-languages-in-startups https://github.com/lucianghinda/programming-languages-in-sta..

[Shameless plug] I also created https://github.com/lucianghinda/programming-languages-in-startups https://github.com/lucianghinda/programming-languages-in-sta... where I tried to add programming languages for top 100 companies from YCombinator and top 50 companies from Techstars. You can find there under /results the list for Scala, but I don't have information how exactly are they using it. Please be advice that the list is based upon resources available on the internet so probably some of them are wrong.