To expand the after-sales services offered for a product purchased by a user, a service server that provides services accesses a specified navigation system, which is the product purchased by the user, using a device ID that is uniquely assigned to the navigation system, and then transmits service information to the specified navigation system. In other words, the service server actively accesses a navigation system, which is fundamentally one of countless terminal apparatuses on a communication network, and provides service information to that navigation system. By operating in this way, a great variety of services can be provided whenever appropriate.