TheBrain has been around a long time. It is not a wiki in any sense. Though, linking notes (called “thoughts”) into relationships is the major structural feature of the software. I posted a script that creates an XML file for import into TheBrain that creates thoughts linked back to selected DEVONthink records. The team at TheBrain have prepared a number of very detailed tutorial videos explaining various use cases for their product. There are OSX, Windows, web-based, and iOS versions that synchronize well with one another.