CMC systems use computers and telecommunication networks to compose, store, deliver and process communication.
Email allows users to send messages to each other.
News groups allow multiple users to discuss the same issues by grouping related discussions into a database divided by subject headings. Both email and news are asynchronous types of communication in that users can send, receive, and read messages at widely separated times. Chat on the other hand is synchronous and real time. Messages are almost immediately transmitted from one user's computer directly to the display of another user or group of users. Though not originally intended, chat systems have had a tremendous affect on the social nature of computer-mediated communication.