All of the major online ad networks - Google, Facebook, etc - actually function like this, and have for the past 15 years. And it is effective to the tune of about $300B/year, looking at Google's ad revenue.
All of the major online ad networks - Google, Facebook, etc - actually function like this, and have for the past 15 years. And it is effective to the tune of about $300B/year, looking at Google's ad revenue.
That's conflating total market with specific benefit though.
If Google ran the dumbest, most basic ad-targeting, their ad revenue would still be >0.
I think a lot of people underestimate the importance of good targeting to the online ads market. It's taken over from print/media/TV brand advertising because it's orders of magnitude more efficient. When Google was young (~2005) advertisers were reporting that they'd get 3-5x more conversions from Google at 1/10th the ad budget because the conversion rate was that much higher.