From Fan History Wiki
Wikia is a corporation that hosts wikis for free. Users of Wikia can create their own. The site was originally founded as WikiCities but was rebranded as Wikia in 2006. 
History in fandom
The earliest wikis for Wikia were fandom wikis for Creatures and Doom. 
Wikia has been active in trying to get fandom wikis to move from their own hosts to Wikia. They were rather active at doing this in 2007. This has been met with varying levels of success. Bulbapedia is one of the wikis to reject them.  The Futurama Wiki is another.  GuildWiki did move. The owner was paid $67,000 to move.  His community was not happy and some splintered off to create their own wiki.
In 2008, there were accusations that Wikia was cybersquatting on the domain that Creatures Wiki needed in order to move off Wikia. 
In 2008, "Wikia attempt to force WoWWiki (wowwiki.com) to move to a .wikia.com subdomain, despite significant objections and little support for the change from the community. " 
Wikia lost several fandom wikis in 2008 and 2009. This includes WikiFur and Transformers Wiki.  Transformers Wiki left in September 2008.