I am aware companies, big companies, use OCaml. My point, perhaps not made clear, is that Jane Street is building useful libs, and contributing back to OCaml with 'batteries included' type libraries. Facebook creating a VM and programming language compatible with PHP may be useful to some, but is not addressing the more fundamental needs or issues like bringing multicore to OCaml.

I think that does a disservice to the much greater number of people who are not at Jane Street but contributing useful code and libraries. You also seem to imply that Jane Street is the one 'bringing multicore to OCaml' but that's not the case.

Jane Street certainly contributes a huge amount to the ecosystem, both in terms of code and other support, but they're not the only people pouring effort into it.