Wiki

A wiki (IPA: /wi?ki?/, "weekee" http://c2.com/doc/etymology.html) is a web application that allows users to add content, as on an Internet forum, but also allows others (often completely unrestricted) to edit the content. The term Wiki also refers to the collaborative software used to create such a website (see Wiki software). In essence, the wiki is a vast simplification of the process of creating HTML pages, and thus is a very effective way to exchange information through collaborative effort.

Key characteristics

A wiki (wikiwiki) enables documents to be written collectively (co-authoring) in a simple markup using a web browser. A single page in a wiki is referred to as a "wiki page", while the entire body of pages, which are usually highly interconnected via hyperlinks, is called "the wiki"; in effect, a very simple, easy to use database.

Related Topics:
Co-authoring - Markup - Web browser - Hyperlink - Database

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A defining characteristic of wiki technology is the ease with which pages can be created and updated. Generally, there is no review before modifications are accepted. Most wikis are open to the general public without the need to register any user account. Sometimes session log-in is requested to acquire a "wiki-signature" cookie for autosigning edits. More private wiki servers require user authentication.

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Pages and Editing

In a traditional wiki, there are 3 representations for each page:

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• The user-editable "source code," which is also the format stored locally on the server. It usually is plain text, made visible to the user only when the edit operation shows it in a browser form.
• A template (possibly internally generated) that defines layout and elements common to all pages.
• The rendered HTML code produced by the server on the fly from the source text when a particular page is requested.

The source format, sometimes known as "wikitext," is augmented with a simplified markup language to hint various structural and visual conventions. Perhaps the most widespread such convention is to use "*" to start a line of text desired to render as bullet-list items. Style and syntax can vary a great deal among implementations, some of which can allow raw HTML tags as well.

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The reasoning behind this design is that HTML, with its many cryptic tags, is not especially human-readable. Making typical HTML source visible makes the actual text content very hard to read and edit for most users. It is therefore better to promote plain-text editing with a few simple conventions for structure and style.

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It is also sometimes viewed as beneficial that users cannot directly use all the functionality that HTML allows, such as JavaScript and Cascading Style Sheets. Consistency in look and feel is also achieved, along with some extra safety for the user. In many wiki implementations, an active hyperlink is exactly as it is shown, unlike in HTML where the invisible hyperlink can have an arbitrary visible anchor text.

Related Topics:
JavaScript - Cascading Style Sheets

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(Quotation above from Foundation by Isaac Asimov)

Related Topics:
Foundation - Isaac Asimov

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Some recent wiki engines use a different method: they provide "WYSIWYG" editing, usually by means of JavaScript or an ActiveX control that translates graphically entered formatting instructions such as "bold" and "italics" into the corresponding HTML tags. In these implementations, saving an edit amounts to submitting a new HTML version of the page to the server, although the user is shielded from this technical detail as the markup is generated transparently. Users who do not have the necessary plugin can generally edit the page, usually by directly editing the raw HTML code.

Related Topics:
WYSIWYG - JavaScript - ActiveX - Transparently

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Standard

While for years the de facto standard was the syntax of the original WikiWikiWeb, currently the formatting instructions vary considerably depending on the wiki engine. Simple wikis allow only basic text formatting, whereas more complex ones have support for tables, images, formulas, or even interactive elements such as polls and games. Many people switch between wiki engines. Because of the difficulty in using several syntaxes, many people are putting considerable effort into defining a wiki markup standard (see efforts by and TikiWiki)..

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Linking and creating pages

Wikis are a true hypertext medium, with non-linear navigational structures. Each page typically contains a large number of links to other pages. Hierarchical navigation pages often exist in larger wikis, often a consequence of the original page creation process, but they do not have to be used. Links are created using a specific syntax, the so-called "link pattern."

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Originally, most wikis used CamelCase as a link pattern, produced by capitalizing words in a phrase and removing the spaces between them (the word "CamelCase" is itself an example of CamelCase). While CamelCase makes linking very easy, it also leads to links which are written in a form that deviates from the standard spelling. CamelCase-based wikis are instantly recognizable from the large number of links with names such as "TableOfContents" and "BeginnerQuestions". Note: It is easy for a wiki to render the visible anchor for such links "pretty" by reinserting spaces, and possibly also reverting to lower case.

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CamelCase has many critics, and wiki developers looked for alternative solutions. The first to introduce so called "free links" using this _(free link format) was Cliki. Various wiki engines use single brackets, curly brackets, underscores, slashes or other characters as a link pattern.

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Links across different wiki communities are possible using a special link pattern called InterWiki.

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New pages in a wiki are usually created simply by creating the appropriate links on a topically related page. If the link does not exist, it is typically emphasized as a "broken link". Following that link opens an edit window, which then allows the user to enter the text for the new page. This mechanism ensures that so-called "orphan" pages (which have no links pointing to them) are rarely created, and a generally high level of connectedness is retained.

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Searching

Most wikis offer the ability to give misinformation...

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By far the most common wiki systems are server-side (Wikipedia is a server-side wiki). In essence, the edit, display and control functions are provided on the server through the wikiengine that renders the content into a HTML-based page for display in a web browser.

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A client-side wiki system only requires the server to "serve" wiki files in much the same way as a web server allows HTML files to be retrieved using HTTP. In this type of wiki system, all the execution required to convert the underlying wiki text into an onscreen formatted display page resides in the client browser. Likewise, the editing tools and functionality reside with the browser.

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The client-side wiki system parallels HTML in that the page becomes a rendering instruction for the browser to interpret.

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Client-side wiki systems may be little more than a code plugin to traditional web browsers.

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Example: Tiddly Wiki

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