I'm a bit new to WordPress which means that my need for using the documentation is pretty high. There is an extensive amount of high quality documentation on wordpress.org, which is great. Unfortunately, the search capabilities are pretty lacking. I put in simple words like "logon" and get nothing found. When using the forum, searching on the name of authors produces nothing found.
I haven't yet done enough with the site I'm developing to know how bad it might be for the users of my blog.
Maybe I'm being a bit picky but it is annoying considering what most sites are capable of nowadays. Still, on balance WordPress is quite impressive.