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.
Shared folders. Share a folder in your Dropbox with others so that you can collaborate on the same files and folders. Changes to the contents of a shared folder are synced with other members almost instantly.hared folders. Share a folder in your Dropbox with others so that you can collaborate on the same files and folders. Changes to the contents of a shared folder are synced with other members almost instantly.