“Userbase” is a project I’ve been thinking about, but will probably never get around to doing, hence its categorisation in the “somedaymaybe” part of this wiki.
In short: Userbase is a web application which does nothing but handle users. The core of it provides user registration, login, preference management, roles, permissions, admin interface, and all that… but doesn’t actually let the users *do* anything. However, it’s the absolute best user management system it can be.
In order for it to do anything, you then install plugins: CMS, blog, wiki, photo upload, discussion forum, project management, workflow, social bookmarking, whatever.
Userbase+Plugins, in combination, would provide a really powerful way to build any kind of community website.
Things I’d want to be in place to make this workable: