This paper focuses upon the visual aesthetic performance of web sites. It describes an experiment in which a site, designed at three controlled levels of visual 'enrichment', was evaluated on a number of measures by two subject groups. The measures used represent the two main facets of the Categorical-Motivation model of aesthetics, and included others specific to the performance of web sites. Using Multidimensional Scaling the results were consistent with predictions derived from this model. They indicate that the drivers of site evaluation were primarily exploratory, 'collative ' variables representing 'interest', 'novelty ' and 'fun'.