[anupamchugh]

>"Marketers can target using demographics, interests, behaviors and tons of other factors to get new customers, or they can upload an emails or other profile data to retarget existing users"

Demography, interests and behaviours are the exact things that what won't be possible without the user's choice now. Coming to your question: small businesses won't have that much first party data to target new users accurately.

>"IDFA has had a global opt-out for years and 30% in the US have turned it off. The new change is to allow the opt-out on a per-app basis after install."

The opt-out feature was buried deep in the settings. Most user never knew it existed. Or aren't tech savvy enough to figure how to disable it

Also, you have a source for this: "global opt-out for years and 30% in the US have turned it off".

I don't think most users even knew that feature until iOS 13. Alright, even if they do, a shift from 30 percent to over 80 percent with a single software update is huge. Still, would love if you could share a source.

[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.