Final answer:
Value-added networks are private, subscription-based multipoint networks managed by a third party, which offer additional services such as secure data transfer beyond simple communication.
Step-by-step explanation:
The networks that are private multipoint and managed by a third party, which organizations use on a subscription basis, are known as value-added networks (VANs). These VANs provide organizations with various services such as data transmission, message switching, and the translation of messages from one communication protocol to another. They are different from public networks like traditional telephone lines or mobile cellular subscriptions, as they offer additional services beyond simple communication. Secure Internet servers are an integral part of these networks, ensuring safe data transfer. These networks do not generally involve electricity production but require a robust electrical infrastructure to support the data centers and server farms that host these secure servers and provide the network services.