A score assigned by search engines that is calculated by measuring an ad's clickthrough rate, analyzing the relevance of the landing page, and considering other factors used to determine the quality of a site and reward those of higher quality with top placement and lower bid requirements. Some factors that make up a quality score are historical keyword performance, the quality of an ad's landing page, and other undisclosed attributes. All of the major search engines now use some form of quality score in their search ad algorithm.
A common video file format created by Apple Computer. Video files found on the Internet are often stored in the QuickTime format - they require a special viewer program for playback.