[manigandham]

Again, that's not how it works. The first-party relationship is between Facebook and its users (who willingly share all that data). Marketers run ads on Facebook by leveraging Facebook's graph and data which it owns.

Also that IDFA opt-out doesn't do anything for logged-in identities as I said before. That's why walled-gardens are so powerful and why privacy regulation has strengthened them even further. There is a big difference between independent adtech, 3rd-party data collection, and anonymous tracking compared to the first-party data moats that Google and Facebook have.