Differencess between internet,intranet,extranet

Internet: Is now the World Wide Web (WWW) network of computers that is dispersedly managed with minimal restriction. It is what you have asked this question over.
Intranet: Operates much the same as the Internet but is restricted to a single corporate entity that has full control and management over it. Able to maximize restrictions over users.
Extranet: is an extension of an Intranet over the Internet for remote users. Typically it is heavily restricted for security reasons to a virtual private network (VPN) connection for Telecommuters or other offsite users.
Ethernet is the standard cable for computers to hook up to the network. It is also used for network devices (Routers, modems & switches) to interface with each other.