The E-I reference system allows users to give other users a "reference" if they have met them in real life and are happy to recommend them. Only users in escort usergroups can give escort references. Only users in the "Established Clients" usergroup can give client references. Where you see a user has references, although you cannot see who gave the references for privacy reasons, this shows you that others have chosen to recommend the user, and may help you decide whether or not to trust him/her.