[bobdosherman]

A lot of this comes down to preferences, and my preference ordering would be:

Ads that attempt to take me all the way from browsing-->discovery-->potential purchase-->purchase I view as always bad. Leave me alone while I'm browsing. Ads that attempt to take me from discovery-->potential purchase I view as ok but ineffective. At least throw a promo code in that ad next time, please and thank you. Ads that successfully take me from discovery-->potential purchase-->purchase I view as ok since my utility is higher having purchased the product given the payload of the ad (and I wouldn't have purchased the product having not gotten the ad).

One thing then from my (not necessarily everyones) preferences is that displaying an ad to me should only potentially be done if the conditional probability of me being in discovery mode is higher than the conditional probability of me being in browsing mode. And then it comes down to what of me is in that conditioning set. Some very fuzzy anonymous slice of me, well ok. But better not be PI in there...

But these are just my preferences, and they may not be representative. So there's an aggregation problem also. In general I'd also prefer if brands shifted the marginal marketing dollar towards channels where the disutility of showing me an ad when they estimate I'm in discovery mode but I'm actually in browsing mode is lowest - so (in my mind) when possible put more in influencer marketing versus google display network for instance. Ideally this preference is evident in brand's roi calcs so it's internalized.