Same podcast, three identity tiers — the player surface decides 1. Web 2: user.ext.eids via cookie sync, full addressability (as in 4). App 3: device.ifa, gated by tracking permission 16. Smart speaker 4: only device.ip — the platform knows who listens, but bidders see nothing. 3-5x CPM spread. See 33 for bid flow.
FIELD NOTES
- Major publisher saw 2.4x fill-rate lift activating universal IDs
- 60% of audio targeting is contextual