[Eridrus]

I used to work in adtech, though not the parts focussed on tracking folks. I think this will cause some disruption for people in the short term, and if Apple stays committed to this line of attack, it could really have a long term impact.

But on the other hand, IP+UA is a very good signal when you don't have a lot of devices behind NAT, and if you just have a Facebook ServiceWorker installed, it could track all of the IP addresses you use. And there is nothing preventing first-party tracking, e.g. what if Facebook starts a "Facebook Publishing Platform" which is basically a section of Facebook.com designed to ensure that you get all the user tracking as before. Or what if publications now ask for "Login with Facebook to read this article".