1. A method of managing content site visitor profiles, the method comprising: under control of a hardware processor: receiving first visitor data from a first tag embedded within a first content page, the first visitor data comprising a cookie-derived visitor identifier associated with a first visitor visiting the first content page; identifying a first identifier of the first visitor from the first visitor data; adding at least some of the first visitor data to a first visitor profile; receiving second visitor data from a second tag embedded within a second content page, the second visitor data comprising the cookie-derived visitor identifier; identifying a second identifier from the second visitor data; determining whether the first and second identifiers are different; and in response to determining that the first and second identifiers are different, adding at least some of the second visitor data to a second visitor profile different from the first visitor profile.