Mailing Lists:
MediaWiki Communication Resources
http://www.mediawiki.org/wiki/Communication
Mailing lists, as well as IRC and Forum information
 

 

 
User Groups:

 

 
Discussion Boards:
MediaWiki Users
http://www.mwusers.com/
"Unofficial" MediaWiki forums
 

 

 
Chat Rooms:
#mediawiki on irc.freenode.net
irc://irc.freenode.net/mediawiki
 
Wikipedia:IRC channels
http://en.wikipedia.org/wiki/Wikipedia:IRC_chan...
Full list of Wikipedia IRC channels