Views allow an application to interact with a user on a social container. The container may have one or more views that an application developer can build content for, enabling the user to view and interact with the application throughout different pages in the container.
Generally speaking, all views will fall under one of two types:
A view that is usually restricted in size and functionality. Small views usually appear on the user’s profile or her personalized home view, which only she can interact with. There may be many small views present on a page, depending on how many applications the user has installed.
A view that usually delivers a fully immersive user experience. This view is seldom overly restricted and will provide most of the same functionality you’d find when developing an application on an external website that you have complete control over. Large views generally have only one application on the page, meaning that users on that view will be engaged only with the application itself.
On most of the current social networking containers, iframes are used to cordon off all views from the rest of the container. While this might provide a small measure of security for the container and its users, it’s far from a secure environment. In many cases, applications will load only after the full container has loaded to prevent performance degradation on pages where multiple applications are attempting to load.