Useful for building an org chart.
Having a problem with client a / contact c ? I know (s)he "Reports To" contact b.
When you display the contact in edit mode, addition "tab" Org Chart listing Who I report To: and Who reports to Me:
When you click into a contact (overview) put the Org Chart either above or below Notes under the contact.
Displayed left column Overview / Contacts / Location / Org Chart for a birds eye view.