Other Wikis dedicated to R:

• R Wiki in Hamburg by Detlef Steuer: http://fawn.unibw-hamburg.de/cgi-bin/Rwiki.pl (although being the oldest one, it is now set as read-only in favor of the current R Wiki, which use a more elaborate Wiki engine).
• R for Mac Wiki: http://wiki.urbanek.info/
• R(D)COM, rcom & RExcel: http://learnserver.csd.univie.ac.at/rcomwiki.
• RjpWiki, a R Wiki in Japanese: http://www.okada.jp.org/RWiki/.
• R extension for Mediawiki: http://mars.wiwi.hu-berlin.de/mediawiki/sk/index.php/R_Extension_for_MediaWiki
  It allows to run R programs and displays results (graphics, HTML and text) of them within the Mediawiki.