Identified users
By default a visitor is anonymous and cannot be recognised across days (see how Lynq counts). A site with logged-in users can tell Lynq who a session belongs to, so a person who comes back tomorrow is the same visitor.
lynq.identify("user_8f3c");Call it once the user is known, for example after login or on every page of the app when a session exists. The id is any string up to 128 characters: your own user id, never an email address. The current session becomes that user’s from the call onward; previous anonymous sessions are not joined to it.
What is stored
The id is hashed with a secret that belongs to the site before it is stored, and the hash is what every report uses. The raw id is not kept unless Store user ids is on in site settings, in which case it is kept for 90 days so you can look a user up.
Global Privacy Control
A browser that sends Global Privacy Control is always anonymous: identify() is ignored and the visit is counted like any other. There is no way to override this.
Effects on the numbers
Identified users count once across the whole range rather than once per day, so a site with logged-in traffic sees unique visitors fall and sessions per visitor rise when it starts identifying. That is the more accurate picture.