I really wish that ads would be targeted based on server side information. As in what website you’re on, or what search term you put in. I really don’t think ads based on my past behavior are useful to me or my purchasing tendencies.
The server fingerprints the user and shares this info with an ad network, fetches and injects a personalized ad. Same result, zero accountability: no way to delete server side PII, no way to know what information was collected, no way to know how it was actually used. Even worse, the server gets to read the ad delivered to you, which may leak even more information.
There is no purely technical solution which can replace regulation.