Wikis are Web-based applications that allow all users not only to view pages but also to change them. The success of the Internet encyclopedia Wikipedia has drawn increasing attention from private users, small organizations and enterprises to the various possible uses of wikis. Their simple structure and straightforward operation make them a serious alternative to expensive content management systems and also provide a basis for many applications in the area of collaborative work. We show the practical use of wikis in carrying out projects for users as well as for maintainers. This includes a step-by-step introduction to wiki philosophy, social effects and functions, a survey of their controls and components, and the installation and configuration of the wiki clones MediaWiki, TWiki and Confluence. In order to exemplify the possibilities of the software, we use it as a project tool for planning a conference.