If someone comes to your site and we don't know who they are (i.e., they're not logged in) we consider them an anonymous visitor. Even though we don't know who this visitor is, we can still personalize content for them using a browser cookie. When an anonymous visitor comes to your site, they'll get a cookie placed on their browser. This will start tracking certain actions, like page views. Using a cookie allows us to personalize the content they see even though we don't know who they are. Then, Rock will recognize them and know where they've been when they come back later. By default, this cookie lasts 365 days, but you can change that by navigating to Admin Tools > System Settings > System Configuration and updating the Visitor Cookie Persistence Length. For all of this to work, you'll need to turn on Enable Visitor Tracking for each site where you want tracking to occur. This setting can be found under Admin Tools > Websites. Ideally visitors won't stay anonymous forever. We want them to log in. When they do, their page views are seamlessly switched over to the known person. You won't need to know this, but for those who are curious, what's happening behind the scenes is your anonymous visitor is tracked under a Person Alias record. When the person logs in, that Person Alias record is linked to their Person record.