[problems]

Yes, it's really that effective - blocking the facebook like button doesn't break most websites.

And typically a request for something like jquery from a CDN will contain little more than your IP address and cookies. You can even prevent the cookies from being sent if you want. The only way they could get away with more than this would be to modifying the resulting script to grab more info from your machine.

[sillysaurus3]

Isn't your IP address plus cookies enough to track you?

[problems]

Yes, but they can be trivially blocked or discarded. My main point is that no advanced fingerprinting tactics can be used so the simple means work in the case of most site-breaking things. Privacy Badger eats CDN cookies - that's actually one of its main features, so it will prevent this kind of thing quite nicely without breaking websites.

[sillysaurus3]

The vast majority of people correlate 1:1 with IP address alone, so I'm not sure how effective this is. Nonetheless, that's pretty cool.

[problems]

Privacy badger also blocks referrers to those sites - having only a connecting IP and asking for a copy of jquery isn't exactly privacy breaching in my eyes. Could be any one of many sites that wants it. Not much they can do with that information.