A screencast is a video recording of a computer screen, usually with audio narration. Often they use special effects to call attention to a specific area of the screen or to actions like mouse clicks and key-presses.
Screencasts are excellent for demonstrating computer software features and how tasks are accomplished. They are a helpful tool for learning how to use computers.
On this web site, the screencast videos are embedded in the articles and play within the browser window when the play button is clicked with the mouse. The playback can be controlled using buttons having the same icons as on modern VCRs and DVD players. Pausing and rewinding are helpful in following along with the video. Working along with the video is highly recommended because it aids comprehension and later recall.