Ask HN: Does targeted advertising work at all?

I'm too lazy to run ad blockers. So I see plenty of advertising on the internet. Here's the thing: all the ads seem to be for things that I already bought. After I placed an order with Select Blinds, I started getting relentless Select Blinds ads on YouTube. After I made some charitable donations to Mercy Ships and Heifer International, their ads started following me around everywhere. My wife recently got on a new immunosuppressant medication, and now I see ads for that all the time. Great job targeting! But I already spent the money? So what is the point of all this?