What are the benefits in using wikis?

If you're looking for solid, quantitative research that proves wikis are THE BEST approach for your team, then I need to tell you that the jury is still out. However, there is a lot of qualitative data to suggest that wikis are providing benefits to individuals, teams, and organizations.

Some of the benefits suggested by wiki users are:

1. ease in creating web-based content, especially by those who have no technical expertise
2. elimination of e-mail threads among groups to communicate or to obtain information
3. ability to complete real-time updates of web-based content (without waiting for the technical support team to update your web server files)
4. avoiding transfer of document attachments to a distribution list through your e-mail system
5. enabling the ability to always access current information (eliminating problems by referencing outdated documents or attachments that you previously received

Tell us your story of how wikis have been beneficial.