The human eye sees 6.5 to 20 f-stops of light. Web and print media get up to 5 f-stops. This means that the eye seems about 3 times as much as can be displayed. If we take a scene that has 10 f-stops (roughly 1000 times more than can be displayed) of range and there was some object that was very bright with good separation from its background, then in real life you probably have 2 or 3 f-stops of difference, but when you put it on a web page, or screen, that difference is lost. The range is colapsed down into the less than 5 f-stops that can be displayed. The result is a rather drab photo of something that was not drab.