ShoutWiki

ShoutWiki is a free wiki hosting service that uses MediaWiki as its hosting engine and is known for its various different, unique MediaWiki extensions. Many of ShoutWiki's staff members are also MediaWiki developers. See ShoutWiki's website or ShoutWiki's about page on ShoutWiki to find out more about ShoutWiki in general.

Extensions
ShoutWiki uses many extensions used by Wikimedia sites, in addition to their custom extensions. The source code for most of these custom extensions can be found either at Wikimedia's SVN repository (the official MediaWiki SVN) or on their appropriate extension pages on this wiki. See Category:Extensions by ShoutWiki for a list of extensions written by ShoutWiki.

Backup
ShoutWiki has been offline for several months. WikiTeam did a backup of 397 ShoutWiki wikis in August 2011. If you want to recover your wiki, just download the package and extract the XML and images. If you have any question, subscribe you to the Google Group.