User

Visitors are anonymously tracked using session ids throughout your site. But when visitors identify themselves at login, signup or checkout, you may pair a session id with a user to identify the entire chain of events one user has carried out over time.

/* Identify a user */
zlt.track('user', {
    'user_id':'john.doe@userdomain.com',
    'email':'john.doe@userdomain.com',
    'first_name':'John',
    'last_name':'Doe'
});

The user_id should be a unique identifier. It can be an email address or any other identifier of choice.