There are four main types of data. <em>Content</em> is the information (text, images, etc.) meant to be displayed to website visitors. <em>Configuration</em> is data that defines how the content is displayed; some configuration (such as field labels) may also be visible to site visitors. <em>State</em> is temporary data about the state of your site, such as the last time the system <em>cron</em> jobs ran. <em>Session</em> is a subset of State information, related to users' interactions with the site, such as site cookies and whether or not they are logged in.