Having worked for these companies some of the data is murky (e.g. did these ads they saw earlier lead to them buying the product later, perfect attribution is obviously impossible) but a lot of it is unambiguous where they tracked people straight from clicking on the ad directly to a purchase. People have their conspiracies but I've seen it in black and white, it's very very clear. The only way I could see the data not being clear is in the case of outright fraud, which I'm fairly certain wasn't happening within our own metrics (as it would not only lead to legal liability but even more importantly fuck up the machine learning models).
Edit: to be clear I would believe the effect of ads is overstated, it's just the idea they are ineffective is wrong and people claiming that you can get more effective ads without tracking people at all doesn't seem plausible based on what I know of the industry. I could see contextual ads working in niche use cases (which again we already see when searching for products. YouTubers have relevant sponsors all the time. We even have affiliate marketing, where it's not only contextual but part of the content).
Tracking somebody from clicking on the ad, through to the purchase doesn’t prove that the ad added any value, though. The ad only added value if the person wouldn’t have otherwise found the product.
Look, none of these criticisms are novel or unknown in the industry and it's well known that measuring the exact impact of ads is impractical but we're not talking exact numbers here, just whether personalized ads are generally effective or not. This criticism effects how effective it is but not the fact that it's generally effective, unless you think all ads are doing is shifting sales forward in time (which doesn't really make sense to me).
I think this is more of an effect for things like search or ads on an e-commerce platform (somewhat ironically the contextual ads people here are advocating for are much more susceptible to this) but less so for a lot of the more random ads, especially for niche products.
Edit: For me they are obviously effective. I think the more interesting question is exactly what the return on ad spend generally is but that would take very specific data that I don't have access to.
Yeah I feel you on this. Anecdotal, but I’ve had plenty of Google searches that ended in what technically counts as ad conversions, but the exact same link is only three items below. The only difference for them is that I clicked on the ad version because it is near the top typically.
Keyword advertising for your company’s own name is a well known mistake: there’s no reason to serve ads to people who are already searching for you. If anything the high conversion rate on that sort of keyword is an argument against… using conversion rates as a metric, haha.
Edit: to be clear I would believe the effect of ads is overstated, it's just the idea they are ineffective is wrong and people claiming that you can get more effective ads without tracking people at all doesn't seem plausible based on what I know of the industry. I could see contextual ads working in niche use cases (which again we already see when searching for products. YouTubers have relevant sponsors all the time. We even have affiliate marketing, where it's not only contextual but part of the content).