What is Remote Media Libraries?
Remote Media Libraries (RML) is a WordPress plugin which allow you to connect external media library such as Youtube, Flickr, Vimeo, Daily Motion, Instagram into the WordPress media library.
You can follow any user in these services, which means the user media will show inside your WordPress media library. As an example if you add The Verge Youtube account, you will be able to see all the public video from The Verge inside the media library and add them to your post.