I'm a long-time user of free/open source software, and write various things for both fun and profit. I don't take myself all that seriously and I do all of my own stunts.
You can find me at these fine establishments on the web: Open Source Musings, The Monday Kickoff, Weekly Musings. and The Plain Text Project.
Authored Comments
Or, you could run your own instance of BookType. It does a solid job of exporting to multiple formats including PDF and EPUB, and is great for collaborating.
A wiki, like anything else online, requires you to be very selective about what you put on it. Even when you're hosting it. Which is another point in favour of personal desktop wikis.