LinkedIn for one:
[1] - https://engineering.linkedin.com/frontend/new-technologies-n...
We built the new version of the home page using Scala because the language adapted itself better to asynchronous programming. With the incorporation of lambda functions in Java 8, it’s possible we’ll be utilizing Java more.
We will have to wait for more people from linkedin to weigh in on this, but it does seem to indicate at looking at other solutions than Scala when they can.