This flowchart illustrates the process of visitor detection. A first-time visitor enters the site and creates a personal profile. The following events occur: The vdm:setalias tag in the template code is used to log the visitor's alias to WebCenter Sites's database. In subsequent sessions, the visitor is automatically recognized. As a result, only a single ID unique to the visitor is kept in the database, which improves performance. Note that memory-centric visitor tracking logs a unique ID per visitor, whereas the existing database-centric method logs a unique ID per visit even for returning visitors. Extra IDs create extra load on the database and reduce performance. Then, the visitor's scalar values (personal information, such as age and gender) are stored to the add-on repository (by custom code). In the remaining steps, WebCenter Sites gathers and computes information that it needs to determine the visitor's segments and therefore which Engage assets to display to the visitor.