Tools exist that look at the usability of sites from a static perspective - for example, looking for broken links. Other tools analyse web server's logs to understand how users behave when using the site. While these tools are helpful, they can only be applied after development and deployment. This paper investigates how a model checking based approach canbe applied to web sites' design to reason about their behavioral properties from the early stages of development. The goal is that analysis of possible interactions between users and a site might be performed before actual development and deployment of the site.