A screencast is a video of a computer screen combined with narration that complements the video. This paper seeks to understand the common elements shared by all effective screencasts. First, I explore what a screencast is, why screencasting is important, and some applications of screencasting. Then current multimedia literature is studied and applied to screencasting. A list of the common elements of effective screencasts is proposed, using current screencasting knowledge, cognitive psychology, and multimedia documentation as a basis. The applications and genres of screencasting, as well as novel approaches, techniques, and shortcomings are discussed as well.