Hi!
In the news this last week, there was some information regarding the usage of Scala by The Guardian, a UK newspaper, and one of the biggest on the planet. I was aware that they were using Scala internally, but it seems they are starting to use it more and more.
Graham Tackley, a developer at The Guardian, talked about that in this video: http://skillsmatter.com/podcast/scala/how-we-mostly-moved-from-java-to-scala – its really worth while seeing this, he talks about how The Guardian uses Scala, and of course talks a lot about Scala itself – so much that this could be a great introductory video for you if you don’t know Scala yet.
One of the most interesting things shown in the video is a search tool / API they created – with Scala – to allow people to search their articles. I loved it, and more so for being open. Take a look for yourself: http://explorer.content.guardianapis.com/#/search?format=json
Thats all for now, see you next time!
JCranky 
Also, people are speculating they are using Play! framework, since it got Scala support few months ago and it is like a revolution on Java web development, concerning these medieval frameworks like JSF, Struts, etc.
Could be, although I’m not sure this would follow their philosophy of limiting how much new stuff they use at once.
They also mentioned using lift-json for, obviously, json parsing, so my bet would be that they are closer to Lift than Play! framework.