> How does NYT enabling ad exchanges enable advertisers to target NYT readers or the NYT website?

tl;dr: My understanding is that an advertiser can use ads on the NYT to profile its audience, then use that profile to target the same audience on cheaper sites.

I can't find the link now, but I've read that this practice is killing the economics that drive the production of quality content. Quality content is expensive but it attracts a higher-value audience, and sites make it with the expectation they can pay for it by charging more for ads shown to that audience. However, that audience also consumes low-quality content, and smart advertisers realized they can get more bang for their buck by running "research ads" to profile the high-quality site's audience, but then target that same audience on low-quality sites.

So ad targeting discourages the production of quality content, and encourages clickbait and memes in its place.

Set the cookie then buy those users later on other cheaper inventory. It's been done for years and entire trade groups like DCN try to battle against it. Nowadays its insider trading with DMPs and data connectors that share ids and segments.

JS injection into display ads, which happens a lot more often than you would think when it comes to ad display network content.