After weeks of trying out several Wiki tools and providers we've finally settled on a solution. The Wiki is self hosted and open to editing. This means that there is no need to create an account to create content. The aim is to lower the requirements for participation.
Will the Wiki become an editable version of the documentation or a new knowledge repository to compliment it? We don't know, we'll the Wiki evolve as organically as possible to serve the community as best as possible. Thank you.