Streaming audio or video is delivered by a streaming server, which can deliver a constant flow of audio and/or video across a network that might be slow or congested. It is much like watching television with an antenna; you will receive only the video that you will be watching immediately. If there is interference in the transmission (i.e., network congestion), the streaming player will compensate by lowering the quality, but it will try not to stop the stream.
In contrast, video files that reside on a web server will be downloaded for viewing, instead of streamed. Viewers will need to wait for enough of the video to be downloaded before they can view it. This can be a preferable means of transmission if you want to preserve the quality of your video for all viewers.
With streaming media, a user does not have to wait to download a file to play it. Because the media is sent in a continuous stream of data it can play as it arrives. Users can pause, rewind or fast-forward, just as they could with a downloaded file, unless the content is being streamed live.
• Makes it possible for users to take advantage of interactive applications like video search and personalized playlists.
• Allows content deliverers to monitor what visitors are watching and how long they are watching it.
• Provides an efficient use of bandwidth because only the part of the file that's being transferred is the part that’s being watched.
• Provides the content creator with more control over his intellectual property because the video file is not stored on the viewer's computer. Once the video data is played, it is discarded by the media player.