ScrewTurn Wiki was a wiki package built in ASP.NET. It is now defunct, but if you’re looking for a good self-hosted wiki alternative, we have two to suggest. One is MediaWiki and one is DokuWiki. They are both great wiki tools, both secure and up to date and maintained etc.
We have experience and expertise at hosting both of these packages, and we actually recommend either. How do you choose which one you want? Check out our post called War of the Wikis where we detail “MediaWiki vs DokuWiki” question.