Documentation in Open Source
I perceive an enormous difference in the amount and quality of the documentation in a number of Open Source projects, some of which is quite excellent. Some examples serve to illustrate my point.
As very good, I'd categorize PHP's "phenomenal manual":http://www.php.net/docs.php which exists in several languages and in a number of different formats. Some other excellent examples include Exim's online specification which is also available as "PDF":http://www.exim.org/exim-pdf-4.60/doc/spec.pdf, both of which clearly show changes between one release and the next. The Apache web server is also well documented in a number of manuals and howtos. Smaller packages such as "fetchmail":http://www.catb.org/~esr/fetchmail/ and "nail":http://nail.sourceforge.net/ are also well documented.
Unfortunately, the OpenLDAP LDAP directory server lacks in documentation. There is a lot of information in the admin guide and in the FAQ-O-Matic and the "manual pages":http://www.openldap.org/software/man.cgi of course, but a lot of useful information can only be pieced together from the mailing lists. What is missing is a comprehensive _all in one book_ sort of guide.
In the category _quite awful_ I'd put the otherwise very good Dovecot IMAP server. Its documents are haphazardly spread across a documentation wiki and a "mailing list":http://dovecot.org/list/dovecot/.
I've used these examples simply to bring my point home. There are hundreds or thousands of other projects which also do excellent work. I confess that to me, quality of code is of course more important than that of the documentation (after all, I can read the source, Luke), I do believe that good software should encompass good documentation.
Oh, and I do of course realize that I shouldn't complain but instead contribute to projects' documentation.