We’re basically forced to switch to self hosting due to the bizarre way Google implements statistics for Google Fonts. 1 out of 1000 requests will include a “tracking font” which is actually invalid and breaks document.fonts.load. This was an incredibly frustrating bug to track down.

Bug for those interested: https://github.com/google/fonts/issues/2345

The guy who is affiliated with Google Fonts who showed up on a thread a few days ago said that he didn't think there was any tracking related to new implementations of Google Fonts stuff.

I guess this says the opposite. Let me try to dig up the thread for completeness...

EDIT: Well that was faster than I thought I'd be able to do. Here's the comment, and the thread: https://news.ycombinator.com/item?id=22369415

I actually don’t care what they’re doing with the data, I care that it crashes the site.

The font that gets loaded once every thousand requests is https://fonts.gstatic.com/stats/Roboto/normal/400 so it’s some form of statistics. But again, my actual concern is that it breaks.

Here’s the code I used to “catch” it. Here, it took roughly 500 requests: https://runkit.com/tolmasky/5e49b314ef61f900146c9a3b

Edit: To be clear, I’m not implying this is something they try to keep secret, just showing a way to observe it since it purposely rarely shows up.

Your users might... But who cares, right?

I don’t think there’s super meaningful data to be gleaned from server-side tracking, especially with browsers increasingly sending little to no information to third party resources. This is CSS, not a JS script that might collect more info and phone home. So yeah, the site going blank is higher priority to me than them knowing if I, the service provider, not my users, prefer Roboto over Open Sans, or if most users now support woff2 vs. ttf. But either way, we’re not going to use them anymore.

CSS can be crafted to conditionally load additional resources, which means it can be a vector for fairly sophisticated information gathering and tracking. For example: https://github.com/kkuchta/css-only-chat