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.
Method 1: Share files using File Explorer. Click the share tab and then choose Specific people. Sharing a folder directly from the Windows File Explorer is a very simple-in a nutshell you simply need to find the folder you want to share and then use the share button to do so.