Museums are increasing access to their collections via web-based interfaces, but are seeing high numbers of users looking at only one or two pages within 10 s and then leaving. To decrease this rate, a better understanding of the type of user who visits a museum web-site is required. Existing models for museum web-site users tend to focus on a small number of groups or provide little detail in their definitions of the groups. This paper presents the results of a large scale museum user survey in which data on a wide range of user characteristics was collected to provide well founded definitions for the user group's motivations, tasks, engagement, and domain knowledge. The results highlight that the general public and non-professional users make up the majority of users and allow us to clearly define these two groups.