As a significant difference to other content management systems (CMS), wiki software offers fewer design options for the layout and design of websites. The primary function, however, is an editing mode for each wiki page, which also allows a newcomer to change the text and content of the page without much training. For this purpose, the wiki page in edit mode is often opened in a WYSIWYG editor or displayed in an easy-to-learn, simplified markup language (e.g. wikitext) (or both). Both variants generally enable font markup, linking, lists and enumerations in particular, as well as the possibility of transclusions for repetitive content in some cases.
In contrast to content management systems with their sometimes precisely regulated workflows, for example in editorial systems, wikis are based on the philosophy of open access: ideally, every user can read and edit every entry.[9] Wikis are considered to have an advantage over a classic CMS when a large number of users post information, so that a critical mass is reached in the medium and it becomes a "self-runner". However, there are also wiki systems that allow access control (e.g. via an access control list) for certain pages and user groups (e.g. departments of a company).
A key function of most wiki products is version management, which allows users to quickly restore an earlier version of a page in the event of errors or vandalism, which are hardly avoidable due to open access.
As is usual with hypertext, the individual pages of a wiki are linked to each other byhyperlinks; the title of a page usually also serves as the link address. Links to non-existent pages are then not displayed as errors, but a form appears to create the new page. Networking with other popular wiki services is partly made possible by so-called InterWiki links.
Most systems are published as free software, often under a version of the common GNU General Public License (GPL). Many wiki software systems have a modular structure and offer their own programming interface, which enables users to write their own extensions without having to know the entire source code.
A wiki can be publicly accessible on the World Wide Web, used in local networks only for a specific user group (e.g. as an intranet) or used on a single computer for personal information organization, for example in the form of a desktop wiki. Examples of desktop wiki software include AcroWiki for Palm OS, Tomboy and Zim for Linux, VoodooPad for macOS, Gluebox (platform-independent), ConnectedText and WikidPad for Windows, and TiddlyWiki, which runs on the client side (without a server) as JavaScript in any browser. Publicly accessible wikis may have restrictions, for example by requiring registration, so that a user account is associated with additional access rights.