Simplify the following text for a Grade 5 native English-speaking person.
Original: Wikia 's growth stems not only from wikis founded on Wikia , but also from incorporating formerly independent wikis that joined Wikia over time , such as LyricWiki , The Vault , Uncyclopedia and WoWWiki .
Simplified: Wikis on Wikia must be about something which lots of people will like , so people can not make them on any topic .