When I visit wiki users in organizations, I often hear stories about how the wiki was brought in by someone who saw the value in using it, and began a grassroots movement to spread awareness and use of it. Not the orthodox way to bring a tool into an organization, because it often leaves IT out of the process until the use of the tool is already underway. It’s happening this way because people are choosing what works best for them, and resisting the idea that they have to use the one tool that’s prescribed as a “one size fits all” solution.
Multiple tools can coexist, and letting people choose can help identify the better tool for their particular needs in the long run. One of the reasons why content and knowledge management systems haven’t been so successful is that they meet the needs of one group pretty well, but aren’t so good for others, so they never reach the level of use that would justify their high cost (once you realize this, it can make you feel slightly duped wondering why software companies would sell something for one group at such a high price, and hide it by claiming it’s a tool for everyone).
The other reason they don’t reach widespread use is simply because the intrinsic push to do something – the internal desire — is a far stronger motivation to start — and keep — doing something. Time and time again people in organizations say to me “we love the wiki, but we have this other tool that’s been mandated as the official solution and we don’t like it as much.