[TheAnimus]

>Your definition of mainstream must differ from the dictionary's.

I have got the same two agents constantly bugging me "oh you know some Erlang right?" at the moment, but the only one that I begin to describe as mainstream is F#.

If your in any kind of LOB space which deals with 'Maths' F# is rampant now. Which is handy for me, as I used to instruct labs on OCaml at uni.

Just using www.inqjobs.co.uk looking in London for contract rates on 500pd+ I find over 20 roles for F#. Compare that to the Python or Ruby number.

That to me, is mainstream. Not quite Java/C++/C# league, but certainly out there.