The visitor ID attribute is used to identify customers using a value that is guaranteed to be unique to each customer. The value is usually set during a qualifying event -- one that would only occur when a customer provides a reliable means of identification, such as registering or completing a purchase.
A simple example of a visitor ID attribute is email address (or email hash). This is typically a reliable way to uniquely identify a customer, especially when it's associated with a qualifying event. In order to accurately perform identity resolution with an email address the following is needed:
Click Next to see how to configure this visitor ID attribute.