On a Contact's Profile page, the Closest Connections section shows the people in your Organization who have the strongest connection to that Contact.
On an Account Profile page, the Closest Connections section shows the Contacts attached to that Account who have the strongest connection to your Organization.
Closest Connections appear only on the Contact profiles for Contacts in your Organization's address book. Contact profiles for your private, unshared Contacts don't display a Closest Connections section. Learn more about the difference between Organization Contacts and personal Contacts
When you turn on activity sharing, SalesforceIQ automatically shares the connection strength for each of your Contacts on the Contact profile page.