You can now see which users you and another user both follow. In this new feature update you will be able to see the users you share with another user on their profile page. As the viewer, you will be able to see the mutual connections of those that you follow with the followers of the profile you're viewing. We hope that this will provide you an opportunity to explore a social proof point that a user is worth following since people you follow also follow that user you're discovering.
This has shipped to GitHub.com and will be available to all user profiles via their github.com/[@username].