Matt Donnelly writes about the unpredictable nature of wikis, and why that’s important for adoption:

Wikis have an exciting, unpredictable quality that’s unavoidable — indeed we should welcome it because it attracts creative thinkers. I know this to be true because that’s what’s happening with our wiki. Not to embarrass him, but if Ted had managed our corporate wiki by imposing a set of predetermined ideas about how it should be used, the adoption rate across our company would be just a fraction of what it is.

This is why adoption of highly controlled, rigid tools usually fails. People need to control how they use the tool, not the other way around.