Wikki It!
One of the things owning a computer will teach is to back everything up. However, even the most paranoid of us can still end up losing precious files--as evidenced by my former host's meltdown which happened to coincide with a computer meltdown on my end. I did have my files backed up on disc, and even started emailing them and uploading them to any available space on my websites (the one advantage to multiple websites), but I still lost stuff, including thousands of fonts that were all saved on a disc. My current burner can't read the disc and chose to eat it instead, resulting in a loss of $800 of fonts I paid for and several thousand that were freeware. Fortunately, my writing wasn't one of the casualties of this particular fiasco. Not only do I have hard copies of everything (in case there is a computer meltdown), but I also have them on the computer, disc, and zip (in case there's a fire and/or computer meltdown). I've even emailed completed work to myself and kept it sitting in a web-based email account. And now I also have a wikki.
MediaWiki is a perfect way for me keep yet another backup of my world building work. It's online, so I still keep computer and hard copies in case my connection is non-existent. It provides an easier way to organize (and thus to find) my work by series and worlds. I don't upload my actual stories there, but use it was a way to keep the background work safe. Easy access, great organization, and yet one more way to backup my work make a Wikki yet another great tool for writers. And it can be set up so only the owner can see the pages beyond the main page. With the registration set so only I can register people, and the options set so only I can modify pages, my Wikki gives me control and a safe place for my work.
Because of my now frequent use of my Wikki, I've created Wikki versions for most of the usual world building templates I use. As with my basic computer/hard copy versions of these templates, I am making my Wikki templates available for use by other authors. Feel free to use them, modify them, and offer them to others. All I ask is for a little note of credit.