1. An autonomous correlation system for correlating user data from a content provider and advertising view data from an advertising provider, wherein the user data is present on one autonomous system and the advertising view data is present on another autonomous system distinct from the one autonomous system, the systems being autonomous in that each is normally secured against unconstrained access by another, the autonomous correlation system comprising: logic to accept a first message from a user, wherein the first message contains an indication of an object being presented to the user, a first user identifier associated with the user by a presenter of the object; a reference database for storing an association between the first user identifier and the user; logic to accept a second message from the user, wherein the second message contains an indication of an object being presented to the user, the object being at least one of a content page and an advertisement, a second user identifier associated with the user by a presenter of the object; and wherein the reference database stores an association between the second user identifier and the user.