The short answer to the question of how does Triton Digital identify listeners for TAP and other services is this:
Listeners are identified in multiple ways, including:
Listener ID is matched to a mobile ad ID.
Listener ID is assigned by a web cookie.
A session-based Listener ID is assigned by Triton when no other ID is available.
For a more in-depth explanation, see How TAP's Frequency Caps Work.