What are some alternatives?
When comparing Referata and Miraheze, you can also consider the following products
Fandom - Anyone can create a wiki!
Wikipedia - Wikipedia is a free online encyclopedia, created and edited by volunteers around the world and hosted by the Wikimedia Foundation.
Oppia - Oppia is a free, open-source learning platform.
TiddlyWiki - TiddlyWiki — a non-linear personal web notebook
LibreOffice - Base - Base, database, database frontend, LibreOffice, ODF, Open Standards, SQL, ODBC
Everipedia - The world's largest english encyclopedia