Help:Description
The Description (or "meta description") of a wiki will be shown on search engines when the main page appears in the results. The description text is helpful for Search Engine Optimization, and tells viewers of search results what your wiki is about. The contents of the system message MediaWiki:Description will be placed inside the content of the <meta name="description" ... > tag of the main page of a wiki.

Added by Dr. Ball, M.D.Background
When main pages show up in Google results, they sometimes have odd text showing as the description. Keywords for the topic of the wiki sometimes appear in boxes and templates on the main page, rather than plain text, so what Google shows can be somewhat random.
MediaWiki:Description is a way for wikis to customize what Google uses as the description for the main page. Right now, it's set to a default: "{{SITENAME}} is a database that anyone can edit." (The term {{SITENAME}} is replaced by the name of your wiki.)
Administrators can edit that page to expand the description, up to 150 characters. Good descriptions include search terms that one would expect people to use when they're looking for your site on a search engine.
MediaWiki:Description in action
- Wookieepedia
- MediaWiki:Description - MediaWiki code on Wookieepedia
- http://www.google.com/search?q=wookieepedia - Wookieepedia on Google search results.
- Wiccana - AoC server
- MediaWiki:Description - MediaWiki code on Wiccana AoC Server Wiki
- http://www.google.com/search?q=wiccana+aoc+wiki - Wiccana AoC Server Wiki on Google search results.
- Warriors Wiki
- MediaWiki:Description - MediaWiki code on Warriors Wiki
- http://www.google.com/search?q=warriors+wiki - Warriors Wiki on Google search results.
See also
- Help:System messages - For editing MediaWiki messages in general
- Help:Pagetitle - On changing the Pagetitle variable.