I bought a new expensive GPU on newegg and now every other week newegg sends me emails about new deals for graphics cards. In what market does that behavior make sense? Most pc gamers probably buy a graphics card once every two years at most unless they're filthy rich.

Its very possible to do this on most ad platforms. Some people are just lazy or aren't good at their job.

Careful what you ask for... being able to exclude you based on a conversion means better tracking.

Tracking is not something that can be easily improved, either you use cookies which are acceptable, widespread, but sadly very limited in functionality or you get into the world of supercookies and fingerprinting which is not yet properly regulated and where a few players are disregarding industry self-regulation to get as much data as possible.

OK. You just bought this paperback, we won't show you ads for it anymore. What are similar things... this hardback version of the same book, are you interested in it?

And Booking.com should just learn to delete all that they know of my searches when I actually book something.

Unless it's coming directly from who you bought the toaster from they can't do that without access to your purchase history which they'd be thrilled to have but I doubt most people would want to give.

Exactly this. How is Amazon smart enough to know I have viewed item X yet not that I have just finally bought it? They should have some "oh, he bought it, let's switch" flag.

Absolutely. I shared my thoughts here: https://news.ycombinator.com/item?id=11750840

Hey bro, wanna buy some bread?