Fandom - The entertainment site where fans come first.

Miraheze - Miraheze is a wiki farm (hosts wikis) for free and with no ads, it also provides custom domains...

Wikipedia - Wikipedia is a free online encyclopedia, created and edited by volunteers around the world and hosted by the Wikimedia Foundation.

Editthis - A free wikifarm project allowing to keep private wiki and build it up through MediaWiki syntax.

Investopedia - Investopedia has a lot of information to share with business mind people.

Wikidot - Online collaborative wiki hosting for organizations,etc.