"Documentation Wiki"—two words to strike fear into the hearts of men. I've been around the block a few times, and seen all kinds of documentation, ranging from excellent to nonexistent. Any documentation is better than no documentation, but of existing documentation nothing is quite as bad as wiki documentation.

Whenever I see one I catch myself rationalizing, "Oh, another wiki documentation site. I think that means it's supposed to be excellent documentation. Buck up and get excited, man! You're such a pessimist." But in the end, my initial nauseous premonition was right.

I'm not sure why this is. Wikis were supposed to be a godsend to documentation efforts everywhere. The community would keep everything perfectly up to date, and the project leaders could focus on the code.

I do have a couple theories. I think my theories boil down to "people are lazy". In fact, a lot of my theories boil down to that. I'd put some thought into whether all of my theories boil down to that, but I'm too lazy. If a project has a wiki for its documentation, then right off that tells you the people that should be writing the documentation are too lazy and are trying to pawn it off on the community. The community just wants to use the software to get things done, with rare exception (usually big projects that are a livelihood to its users, e.g. Asterisk). The people in the community that aren't too lazy to make an account, evade spam protection, and do enough research to (attempt to) write a quality snippet of documenation are too lazy to come back and update that documentation at every new release. They might not even use a new release for months or years after it's released, because they keep using the version that's working fine. Or maybe they're on the other end of the spectrum and they follow the bleeding edge religiously and update the wiki with vigor. Oops, now the stable dinosaurs don't have any documentation for the version they are running. Oh, and those lazy devs spend more time cleaning up spam in the long run than they would have in writing quality documentation which would have been better for everyone in the first place.

Unless your project is very important and your community is very vibrant, forget the wiki. Just bite the bullet and write some docs. Or, ask someone in the community to head up the effort (the slightest bit of organization will go a long way here). For the best of both worlds, write the documentation and put it in a wiki where people will update it as they notice it is needed. The laziness threshold for fixing a small problem in an existing documentation page is small enough (unless you require registration and spam hurdling).