Wikis as public palimpsests
A wiki is a collection of web pages that can be edited by anyone, at any time, from anywhere . The overriding goal of a wiki is to become a shared repository of knowledge with the knowledge base growing over time (Godwin-Jones, 2003). According to its original creator Ward Cunningham, “a wiki is the simplest on-line database that could possibly work.” (Leuf & Cunningham, 2001). It is “a freely expandable collection of interlinked web pages, a hypertext system for storing and modifying information - a database, where each page is easily edited by any user with a forms-capable Web browser client“ (cited in Schwartz, Clark, Cossarin & Rudolp, 2004). Browser-based access means that neither special software nor a third party webmaster is needed to post content .
What is unique about wikis is that anyone in the world can change anything in a wiki page. That is, no one authorizes the creation of wiki pages. Everyone is automatically (by default) authorized to write, edit and publish. However, not only can people write, edit and publish their own work, they can rewrite, edit and even “un-publish” the work of others. This “un-authorization” in terms of ideas and their dissemination applies not only to content, but also to the organization of contributions. Hence, by definition all wiki content is “work in progress,” or, in wiki language, WorkInProgress. (Some important theoretical and pedagogical implications and consequences of open editing are outlined in the Pedagogical Potential section.)
Wikis have been described as analogous to “open, three dimensional ThreeRingBinders” (JohnDeBruyn in reference Category Wiki-1), as “FlyPaperForIdeas” (References, Category Wiki-5) as collaborative stories (References, Category Wiki-8) and as “mindmapping using keywords” (References, Category Wiki-5). A seemingly apt metaphor for a wiki is a Palimpsest.
Wiki is Hawaiian for quick. (Yes, there is a real “wiki” in Hawaii: a bus at the international airport in Honolulu). "Wiki" (with a capital “W”) is shorthand for the WikiWikiWeb, otherwise known as “WardsWiki” (Ward being the author who created the original wiki website). A “wiki" (with a small “w”) is a site that operates along the same principles as WardsWiki. The best-known wiki is probably Wikipedia, the free encyclopedia.
Wikis are lightweight collaborative technologies. They are people-centred tools (Brereton, Donovan, & Viller, 2003). As such their design is intentionally basic. While images can be added, wikis are primarily text-based. One can write text directly within a wiki page on-line or copy and paste text from a word processor. Text formatting to date has been extremely simple, with each wiki determining own simple markup language styles. However, more and more wikis, especially in educational contexts, are being configured to use what is referred to as a “What You See Is What You Get” (WYSIWYG) interface. (SeedWiki  is an example; see also http://www.ariadne.ac.uk/issue42/tonkin/)
Wikis are Open Source Software and are often part of the Free Software Movement -FSM (free as in freedom). Wikis typically use GPL (the Gnu Public License) . “The underlying philosophy of the FSM (and these wiki tools) sees the source code as a public good, not to be owned nor controlled by any one group or person.” Daignault (in process; 2001) makes the case that the values underlying the FSM model of public knowledge dissemination and mobilization have both strong ties with and important implications for educational theory and practice. The underlying technology of these new tools is XML (extensible markup language). XML separates content from formatting, encourages the use of meta-data, and enables machine processing of Internet documents. “The latter is key in the ability to link automatically disparate documents of interest to individuals or groups. The new collaborative opportunities this enables have led some to consider the growing importance of XML as the signal of the arrival of the second-generation Web” (Godwin-Jones, 2003).
Blogs are often quite structured, while wikis are more flexible. Blogs are chronological whereas wikis can be organized in innumerable ways (subjects, categories, hierarchies, etc). Wikis include a search feature, whereas many blogs do not. Once a blog message is posted, it cannot be edited by others. Wiki pages can usually be edited by anyone. (Wiki pages are, by default, open but they can be configured to give selective access, or may even be entirely closed.) And while blogs can be highly personal, wikis are intensely collaborative (Godwin-Jones, 2003). 
The tools we use may matter. According to Idhe "Technologies transform our experience of the objects in the world non-neutrally." (1994). Daignault (2001) argues that if this principle of non-neutrality is upheld, technology will reflect the interests of a given collective and will give rise to both creative and destructive tensions concerning its use. The collective tensions created by wikis — for those who dare to risk living them — may radically alter pedagogical praxis. Wikis’ collective, open structure redistributes the traditional (i.e. academic) knowledge-power nexus along non-authoritative lines. Some ensuing concerns for academics writ large are presented in the About Research section.
You are invited to co-author and rework this text. Perhaps in this “WikiWay”, we can build a critical and creative database about these intensely collaborative and particularly open (which is to say, leveling) tools. Go to WikiPedagogy to contribute in English, and/or WikiPédagogie to contribute in French if and when the text gets translated.
 For those interested in wiki history, wikis began in 1995; see Cunningham or Aronsson.
 According to Schwartz et al. (2004), this eliminates the need for distribution with the associated risk of virus transmission
 The GPL license (often called the GNU GPL) is the most widely used license for Free Software projects