Wiki documents are meant to be edited. Posting content to a wiki allows others to discuss and edit the content, making productive collaboration on written content possible. Settings can be adjusted to determine who can edit in the wiki space.
The "history" section of a wiki charts the specifics of revisions: who made the revision, when they made it, and what it was. In addition to tracking revisions, wikis allow users to revert back to an older version if necessary, making editing collaboratively stress-free.
A wiki starts off as a single-page, but the number of pages that can be created are endless. Wikis allow for linking from one page to another, but by nature they are lateral rather than hierarchical, which means that "all pages are equal."
Creating a course-related encyclopedia or glossary is one of the most popular uses of course wikis. Maggie Debelius, for example, had her undergraduate English students compose biographical entries on the various "new women" that they were studying in the course. This gave them the opportunity to take charge of authoring a component of what became a collaborative compendium on their course material, while at the same time being able to contribute to their classmates' encyclopedic entries.
Group projects rely on collaboration and communication, and a wiki provides both. Loredana DiMartino, who teaches Intensive Italian, divided her students into four groups and asked each of them to compose an Italian fairy tale using their own group pages on a course wiki. Sharing a wiki space allowed the student groups to compose in a place visible to their classmates as well as edit their group members' work. A wiki "history" tab allowed Professor DiMartino to track the students' edits and participation.
Wikis also make a good place for students to create shared study guides and a course note repository. Students in a biology course, for example, collected course notes on a wiki. When collated from and edited by all students in the course, a course notes repository becomes an invaluable study aid.