From Seo Wiki - Search Engine Optimization and Programming Languages
It is notable because it was one of the largest projects being developed while PHP 5 was still in early development.
The creator, Daniel T. Gorski, began development of coWiki in December 2001 as a weekend study to learn how a wiki works.
The first release (0.2.0) was in March 2002 for the BLUE MARS GmbH intranet.
Daniel began to look for new maintainers for the project on January 3, 2005. New maintainers were found on January 12, 2005, lead by Paul Hanchett.
Development soon moved into the open source software host tigris.org, where the 0.3.4 maintenance release was completed by the new staff on February 24, 2005.
By April 2006, the maintainers did not have the personal time to spend on the project, and on June 13th 2006, maintainer status was changed to include some new people. By November 2006 there was no development activity and very little mailing list activity.
On November 7th 2006, it was announced that the cowiki.org website would be taken down and archived, awaiting a new team for the project.
As of November 2006, coWiki is still used in a production capacity on personal and corporate websites and intranets. Daniel and a handful of other developers still offer consultation services and custom-programming focused around coWiki installations.
Commentary from the website on 13th December 2006: After almost five years of evolvement of the coWiki web collaboration software project, the development has been discontinued. The project passed away... Alas, all I must now sadly say is: R.I.P. coWiki.
The "bad magic" bug
The website says If you find it, do not install it - it is evil and will destroy you data sooner or later.. This problem was dubbed "bad magic".
A page would roll back to an earlier version. No references could be seen in the site or page history/changelogs. Edits would simply vanish. This was most notably seen on the homepage and it is possible (but not confirmed) that it could have happened on other pages.
At first, it was theorized that this bug would happen on installations which are heavily-trafficked and allowed public editing, as Sy's installation allowed. However, the coWiki.org website did not allow public editing of or commenting on its main page. Even after significant research and rewriting, this mysterious problem could still not be eliminated. It was a major blow to the project.