I've said this before on here, but online advertising is incredibly dumb. If you consider all the info Google and Facebook have on me, it's a really sad state of affairs.
I bought a new bicycle and religiously researched this topic and consumed a ton of cycling videos. What ads do I see on YouTube? Cars. I don't have a driver's license.
I once bought a NI Maschine Midi Controller. YouTube then showed me video ads for the NI Maschine Midi Controller for over a year after the purchase. Great business for Google, not so much for Native Instruments.
During a vacation in South Korea, I had logged into Facebook to post a picture. Facebook then showed me Korean ads in Hangul for over a month after my return. They have all the info on me, where I was born, what language I speak, where I live, where I work. Hilariously bad.
And so on.