I think it would be a great place to add style guides and basic knowledge for all programmers using the same instance (in a company) of gitlab.
It would be a great place to record installation issues and how we worked around them in our installation.
Why this issue has been closed ?
Feature requests now go to http://gitlab.uservoice.com/forums/176466-general
I guess that http://gitlab.uservoice.com/forums/176466-general/suggestions/3159951-allow-public-repositories is similar to this request, consider upvoting it
I think the OP was not about having a public wiki (visible by people outside the company), but about having a "shared wiki" that doesn't depend on a particular project
We have created a project on the root folder and added all employes as members. It works as a common Wiki, as an Issue tracker for mis-configuration bugs or internal complaints about how Gitlab works and as a place to store common configuration files.
I think the root folder is perfect for this. You can even have multiple repositories there. It's all about picking a good slug, like gitlab.mycompany.com/meta, or gitlab.mycompany.com/shared, or gitlab.mycompany.com/wiki.