We're big on Yesod for web apps, so we end up using Haskell for both presentation and crunching the analytics that are shown to teachers and administrators. We have a bunch of internal Haskell tooling for our content pipeline. Upcoming ETL work is going to be Haskell-based as well. Still trying to figure out what to do with our monster Clojure codebase we have our API in, really tempted to port it, but there hasn't been time yet.
