Other webby things in OCaml include Ocsigen project [1], which is where js_of_ocaml and Lwt came from (for a while there was also the web framework Ohm, but I think development stopped). There are probably many others that I'm not yet aware of.
Personally, I'd love to have a blog-aware static site generator in pure OCaml, that's as straightforward to set up and use as Jekyll -- major bonus points for also being OPAM-aware [2], so you can easily include your packages and docs. So far I haven't found one but I can't be the only one to want this.
[2] OPAM is the package manager for OCaml.
Edit: I've now added the static-site idea to the MirageOS Pioneer Projects page https://github.com/mirage/mirage-www/wiki/Pioneer-Projects