A starred contact can mean anything you want it to mean. When the product was young, users requested a way to favorite or separate certain contacts from the crowd. We took that request and created the star system.
Maybe you'd like to keep your hot leads or VIP clients on a separate list. Maybe you'd like to identify your most challenging contacts or your biggest customers. Simply click the star next to their name.
Once a person is starred they will be placed on the "Starred" list under the People tab.