Fully Supported Forums:

phpBB
vBulletin
IP.Board
Simple Machines
Drupal Forum

Forums Fully Supported but undergoing in-depth testing:

UBB / UBB.threads
invision
ezboards
ProBoards

Identified Forums which have been untested:

MyBB
ProBoards
Burning Board
Beehive Forum
Extreme Message Board
Advanced Electron Forum
FUDForum
FluxBB
FusionBB
IP.Board
IceBB
Joomla Forum
MesDiscussions
MiniBB
Phorum
punBB
Quicksilver Forums
SEO-Board
Social engine
UltraBB
Unclassified NewsBoard
USeBB
Vanilla Forums
Viscacha
wtcBB
Wikid Forum
Woltlab Burning Board
wowBB
XenForo
XMB
bbPress
esoTalk

 

Non-PHP Forums:

YaBB (Perl)
Jforum (java)
JavaBB (java)
MVN Forum (java)
Yazd (java)
Comm100 Forum (.net)
NearForums (.net)
Yet Another Forum (.net)

 

Hosted Forums:

Answerbase
BulletinBoards
ForumCommunity
Forumotion
FreeForums
Google Groups
Lefora
Nabble
Ninja Post
Nitpick
Tal.ki
Twelvestone
Website Toolbox
ZetaBoards
Zoho Discussions