Wikis are versatile.
I like wikis because they are versatile, they offer a fairly quick start-up and they are simple to navigate.
Want a public/private space for an ongoing community calendar that allows members to comment and edit and records changes? A wiki can do that. Other resources can do it too.
Want a public/private space for community development of a mission statement that allows member editing and discussion and records a revision history? A wiki can do that. Other resources can do it too.
Want a public/private space for the ongoing creation of a collective resource that allows member editing and records a revision history? A wiki can do that better than most similar tools that serve as collaborative publishing environments.
I have seen a professor use wikis in his I/O Psychology class. Every semester, a new class adds on to and revises existing content in the wiki. Each semester the resource gets a little more comprehensive and the content becomes more concise with a deeper level of analysis.
Who are the Wiki Police?
When ascertaining quality in a wiki, one probably ought to consider the age of the resource as well as the size of the developer community, since (theoretically) the quality should improve as additional contributors continue to evolve the resource content over time. In the practical application of a wiki, however, any community member has the ability (and right?) to come along and highlight something that they don’t like or don’t agree with and hit the delete button. Wikis depend on the knowledge, abilities, motivation, and integrity of every community member; so, the capabilities of open contribution and immediate updating can become either advantages or drawbacks.
Wikis in the Classroom –
In the case of wikis in formal education where students are unlikely to have a level of expertise on the subject matter, quality as defined by accuracy of content and the use of an academic writing style with appropriate formatting and citations will require policing by an instructor.
Public Wikis –
In the case of public wikis, quality is policed by the users. Expert users may be tasked with oversight as site moderators. Users may be asked to report content that falls outside the acceptable range as established in a community administrative document. Still, some might refer to wikis as crowdsourcing knowledge, but I agree with Marcio Saito in that it is important to remember the 1% Rule here. (Jakob Nielsen calls this Participation Inequality.) The 1% Rule suggests that 1% of the community will create the content, 9% will edit and modify that content, and 90% will view the content without making a contribution.
Wiki as a Teaching Tool by K.R. Parker & J.T. Chao