That’s not “the issue” with my first point, that IS my first point.
In a perfect world, a “reasonable ad” shows you exactly what you’re looking for, without leaking any information about yourself. I understand that it’s tempting to say that’s not possible, but “proof by not being able to think of a solution” isn’t a proof, that’s why I’m hesitant to make such a strong claim.
Zero Knowledge proofs were thought of as impossible until it turned out they weren’t. Can someone serve “Zero Knowledge ads”? Maybe one day, idk.
Even if you don’t like ads, you can’t deny that they’re a powerful means of funding projects that otherwise can’t be sustainably monetized. We learned this lesson 20 years ago when the first federated internet platform hit the mainstream: the world wide web. So imo there’s no reason to think the fediverse isn’t about to relearn the same lesson.