A broadcast is a transmission of information to a large group of people. Originally, it referred to radio and television broadcasts. Today, it also describes digital broadcasts sent over the Internet.
Early broadcasts, such as AM and FM radio, were produced using analog signals transmitted over the air on different frequencies. In the early 2000s, several over-the-air or "OTA" broadcasts either converted to or added digital signals, such as HDTV, HD radio, and satellite radio. Today, many broadcasting companies transmit both analog and digital signals.
Internet broadcasting is the distribution of content from a single source to multiple recipients. It is similar to multicasting, but does not limit the number of users. For example, a multicast may transmit a video stream to 50 people, while a broadcast is available to all the users who tune into the stream. Most streams are considered broadcasts since they are not targeted to specific users.
Similar to a radio broadcast, which only transmits one signal, an Internet broadcast only sends one copy of the data. However, Internet broadcasts are not limited by physical distance and are accessible to users around the world. When individuals connect to a stream or other Internet broadcast, the data is rerouted to multiple locations. By the time the broadcast reaches all the connected users, it may be duplicated hundreds or thousands of times.