contrast to high-traffic mailing lists which may burden subscribers with many messages, regardless of their relevance. It is also very useful for the project manager to have all the communication stored in one place, which allows them to link the responsibility for every action taken to a particular team member. Organizes information. Wikis help users structure information into discoverable and searchable categories. These may arise from users in a bottom-up way. Users can create lists, tables, timelines and other ways of expressing order. Builds consensus. Wikis allow structuring the expression of views, on a topic being considered by authors, on the same page. This feature is very useful when writing documentation, preparing presentations, when author opinions differ, and so on. Access levels by rights and roles. Users can be denied access to view and/or edit given pages, depending upon their department or role within the organization. Knowledge management with comprehensive searches. This includes document management, project management, and knowledge repositories useful during times of employee turnover or retirement. Personal wikis Software that is specifically designed for running personal wikis includes Tomboy, PmWiki, and ConnectedText (now discontinued). Other, more general, wiki applications have components geared for individual users, including MoinMoin (which offers a "DesktopEdition"), and TiddlyWiki. Editing Most wiki software uses a special syntax, known as wiki markup, for users to format the text, instead of requiring them to enter in HTML. Some wiki applications also include a WYSIWYG editor, either instead of or in addition to the wiki markup editing. Based on the atomic property of database systems, any edit should be traced. On wiki software, the chronology of edits (e.g. published by Internet users) in any given article may be locally saved with a common .xml file extension by people having administrator rights. Hosted application There are a variety of wiki hosting services, otherwise known as wiki farms, that host users' wikis on a server. Some wiki software is only available in hosted form: PBworks, Wetpaint and Wikispaces are all examples of wiki hosting services that run on code that is only available on those sites. Other wiki software is available in both hosted and downloadable form, including Confluence, Socialtext, MediaWiki and XWiki. Additional features Content-management features Wiki software can include features that come with traditional content management systems, such as calendars, to-do lists, blogs and discussion forums. All of these can either be stored via versioned wiki pages,