<p>Looking for a good choice of .NET-based Wiki Platform.  Doesn't need to be Open Source, but the cheaper the better.</p>

Linked Note
SharpForge
is an asp.net 2.0(c#) project management application, released under the new BSD license. Each project has its own wiki. Rather than using a special syntax the wiki uses standard HTML. Content is versioned in the version control system.
FlexWiki
is written in C#, uses the .NET framework, and stores data in files or Microsoft SQL Server. FlexWiki is an open source wiki software, released under the CPL (binaries and source code available for download).
Perspective
is written in C#, uses the .NET framework, and stores data in XML files. Binary and Source Code are available for download.
SharpForge
is an asp.net 2.0(c#) project management application, released under the new BSD license. Each project has its own wiki. Rather than using a special syntax the wiki uses standard HTML. Content is versioned in the version control system.