Lack of marketing I guess, not many users, and may be because people panic when they cannot immediately find the thing they are familiar with, for example OO hierarchies, dynamic types. Plus I found it hard to understand till I got a rudimentary understanding of OCaML, and Haskell's typeclasses. So its not ready to be used by everyone.

To do something nontrivial with it you would need to be on the mailing list though.

@dllthomas as far as I know OCaML doesnt, by no standards am I an OCaML user, although want to get better.