I've been using ikiwiki as my private wiki for several months now, and have been very happy with it.

It's the ultimate geek wiki. You get:

  1. A simple, yet well-known default input format, markdown.
  2. A real version control system of your choosing, as opposed to some ugly bolted on custom thing (I chose git).
  3. An ability to edit the content using your favourite text editor, which is, frankly, a huge improvement over HTML text areas.
  4. It is written in Perl, and the code is reasonably clean and well thought-out. Since Perl is the language I've been using the most, it is a pretty big bonus for me.
  5. The actual wiki content is a collection of generated static HTML pages, so you don't actually have to think about CPU resources spent by the server.

Those are the big points. You get much more than that, of course, but those were the sellers for me personally.

Ikiwiki can also work as a blog, and since today, it powers this blog as well. I'll do a comprehensive writeup on what it took to convert this blog from Movable Type to ikiwiki once I am reasonably sure everything works to my satisfaction.