The Wiki tool is a collective or collaborative redaction tool. It allows users to work together on a single document, and to follow the history of modifications. It also allows you to save time and be more efficient during a group task. In many ways, it complements the forum tool.
A wiki page can contain many links to other pages, which may or may not (yet) have existing content. Wiki pages can be updated; each contributor sharing the same rights to write and edit content. Originally designed to support collaboration between learners, the wiki may, at the beginning of a course, consist only of a list of links inserted by the teacher, pointing to empty pages which each learner will have to build using one another's ideas, views and experiences.