[hylaride]

That's the point. Youtube/Google knows who I am and I'm logged in - my preferences are all set to english and my searches, videos watched, etc are all 99% english, with the rest being with english subtitles.. I'm not talking about banner ads on random websites.

They literally have first class data.

[shadowgovt]

Good point. Another hypothesis is that individual advertisers aren't using that data.

Back in the day, I had a front-row-seat to this process and I observed how often advertisers simply misconfigure a campaign and under-target it. If you don't set a targeting preference for a given indicator, the default can be to target everyone regardless of what that indicator says about them.

It might be the case that advertisers are saying they want to target you anyway (or failing to say one way or the other) even though they should have enough signal to know it's a wasted impression.

[hylaride]

Yeah, that makes sense as well. The french ads come to me in waves and I can see lazy advertisers just "targeting quebec" or "all french regions" for the french runs.