Fandom - The entertainment site where fans come first.
ZuluPad - ZuluPad is a notepad on crack.
Miraheze - Miraheze is a wiki farm (hosts wikis) for free and with no ads, it also provides custom domains...
Wikiful - Wikiful is an online platform that makes it easy to build and share a wiki.
Wiki on a Stick - Self-contained desktop wiki
Editthis - A free wikifarm project allowing to keep private wiki and build it up through MediaWiki syntax.