A site is a directory for your organization.  Sites are not websites. Sites organize your applications for source control and deployment.  Users have no perception of sites.  Currently, the site setup is automatic.  If you specify a sitename that is not in use, Dynamide will create that site when you create the first project.  Sites allow you to easily share libraries of components between a group of applications.

An application is a series of web pages that serve a common purpose.  You can have multiple applications within a site.  Applications always start with the same URI, such as /myapp or /foo/myOtherApp.  

When a user uses an application, they get a Session until the Session times out, which is configurable.  All values in the Session are saved in memory on the webserver until the application decides to persist them.  Multiple users using the same URI would get multiple Sessions.  Sessions are usefull for remembering user state, such as shopping carts.  Valuable data should be persisted to a datastore, but the Session can pool datastore connections, etc.

A Page is a web page.  The contents of the web page can be dynamically altered by Dynamide and you application code. You can have an application with one Page object that is modified by the data available and the user's actions. When the Page's contents are very different, it is easier to design a new Page object, and use Dynamide's page flow features to present the pages in the correct order.

A Widget is a component that contains a layout template, properties, and method. Widgets are added to Pages. They can be coded by hand, or built using the Dynamide IDE.