If you are a developer in AdTech, you will NEVER hear about interaction, or see contract, with most of the companies listed...other than a handful (maybe FB, maybe Yahoo, maybe Instagram). I've worked for Experian (the US Company) and talking about them in the AdTech space is the same as talking about HN in the cooking recipe space. There's a tiny bit of overlap, but it's largely pointing to shoehorned third parties because that isn't something Experian's existing infrastructure performs.
AdTech is fun, it pays well, and you get to be at the ground level of these moral compass debates. I have refused some pieces of work and AdTech is tolerant to negotiating concerns. I think most developers would benefit from experience in AdTech, even if it's just a short time.