Many large online providers offer a variety of content sites (e.g. news, sport, e-commerce). These providers endeavor to keep users accessing and interacting with their sites, that is to engage users by spending time using their sites and to return regularly to them. They do so by serving users the most relevant content in an attractive and enticing manner. Due to their highly varied content, each site is usually studied and optimized separately. However, these online providers aim not only to engage users with individual sites, but across all sites in their network. In these cases, site engagement should be examined not only within individual sites, but also across the entire content provider network. This paper investigates inter site engagement, that is, site engagement within a network of sites, by defining a global measure of engagement that captures the effect sites have on the engagement on other sites. As an application, we look at the effect of web page layout and structure, which we refer to as web page stylistics, on inter-site engagement on Yahoo properties. Through the analysis of 50 popular Yahoo sites, a sample of 265,000 users, and 19.4M online sessions, we demonstrate that the stylistic components of a web page on a site can be used to predict inter-site engagement across the Yahoo network of sites. Intersite engagement is a new big data problem as overall it implies analyzing dozen of sites visited by hundreds of millions of people generating billions of sessions.