Are you talking about Scala or Clojure? I've only seen those names mentioned with their Scala use, what are some of their Clojure projects?
Netflix: they definitely use it for Hadoop stuff, probably elsewhere too. And from this presentation they do a fair bit of Java interop with it: https://speakerdeck.com/daveray/clojure-at-netflix
Twitter/BackType produced Apache Storm, which is written in Clojure.
Not sure about the Guardian, I should ask, but they're definitely using it.
Are you talking about Scala or Clojure? I've only seen those names mentioned with their Scala use, what are some of their Clojure projects?