Another cool one from CUFP this year is how Facebook is using OCaml to add incremental type inference to their vast PHP code base. There's (slightly hard to see video) here, but I'm sure Facebook will publicize it more widely when they're ready.
That acm article was very interesting, than you! Lots of nice little
concrete examples - that are simple, yet not too simple.
I've yet to play much with ocaml — we had a bit of standard ml in our
programming paradigms-class at university (at the time the course used
[1] "Programming Languages: Concepts and Constructs (2nd Edition) by
Ravi Sethi" — now they've (unfortunately, yet understandably) replaced
standard ml with Haskell). I've since had a little trouble adapting to
similar-yet-different languages like both Haskell and OCaml.
ocaml.org have a list of users: http://ocaml.org/companies.html
Some "big" companies in the list: Facebook, Citrix, Dassault Système.