Identifiers can be created via human-provided methods (authentication) or via system-generated methods.
System-generated methods can assign an random identifier (e.g., alphanumeric or pure numeric identifier, such as often stored in cookie ID, MAID, CTV device ID) or rely on algorithmic processes to transform network and web-enabled device characteristics into an identifier (e.g., digital “fingerprint”). Such algorithmic processes are often used to identify non-human traffic (robot scripts) to filter content matching, but these same identifiers are discouraged from use for pro-active content matching.
An identifier can be cross-publisher (aka as cross-domain), to support use cases such as reach, frequency capping, attribution and optimization. An identifier can be site-specific, to support engagement.
Linkages Among Identifiers
The linkages among identifiers (across sites or devices) can be either “deterministic” (joining identifiers via identity) or “probabilistic” (joining identifiers not using identity, but instead by some algorithmic method).