The design of a website represents its aesthetic appeal. Be it through clever programming, art work, or an engaging layout, design creates values for a website through its ability to produce higher quality returns from the user base. By establishing a brand of quality, and a sense of sophistication, users are more likely to engage the asset through value-creating transactions.
However, as with many aspects of a web-page, the subjective nature of design means that it can be difficult to evaluate just what kind of benefit the aesthetics of a page are creating for the bottom line. As such, the best way to evaluate design is through the opportunity cost of its creation, the end-user benefit that is created through the enhanced interface, and the traffic benefit that is generated from the sheer appeal of the aesthetics.