Unix System programming in OCaml

It is my pleasure to announce that Xavier Leroy and Didier Rémy’s course on Unix system programming in Objective Caml is now available in english at this address :
http://ocamlunix.forge.ocamlcore.org/
If you had a look at the individual publications of the chapters announced on the project feed you may want to have a look again: some parts of the text were improved and a few translation errors were corrected in the final version.

This course looks like a lot of fun!
(via caml-list)

Is OCaml's standard library its weakest link?

In this post I read that:

OCaml’s standard library is one of its weakest parts. Always use extensions to the std library.

Searching around the net I find ExtLib, Batteries, and Janestreet.
I’m not sure what “weakest link” meant in the original post so I will leave it wide open for any concerns that people have. Perhaps it means that it does not have enough functionality? Or slow? Or there is something odd about the APIs?
It is true that OCaml’s standard library is its weakest link?