Members of the site each have a user profile and can upload research output including papers, data, chapters, negative results, patents, research proposals, methods, presentations, and software source code. Users may also follow the activities of other users and engage in discussions with them.
Here is the official word from Microsoft TechNet, The C:\Users folder is shared when any sub folders from C:\Users\<username>\ is shared. The article is stale and mostly unhelpful, but worth knowing to complete the story.
Please remember that sharing account logins is prohibited and violates the AHCCCS User Acceptance Agreement. You should NOT share your user name and password with any other individuals. Each user must have their own web account. Access to the web site can be terminated if the User Acceptance Agreement is violated.