I bumped into this while reading various things:

http://beebole.com/blog/2008/09/02/web-application-on-erlang/

And was interested, because it fits nicely with a half-formed idea of my own: Erlang is never going to be a nice language for doing HTML templates, but getting JSON into and out of it is pretty easy, so it could potentially work very well where your application is divided between Javascript for all the template/rendering/frontend duties, and Erlang on the server, with something like Mnesia, Couchdb or Postgres as the data store. That sort of application wasn’t really possible several years ago, but with the right target audience, you could probably get away with doing an app that requires Javascript to function these days.