Firefox

What are you talking about? If the logic and metadata is completely stored in your machine, there's no privacy violation. The ads themselves don't need any PII unless you opt in to some kind of profit sharing system (e.g. you get paid to see ads), and that can simply be handled by the browser itself (i.e. a cryptographic signature that can only be verified client side).

As for not liking injecting stuff into a browser, what about browser extensions show you if another site has a better deal on something? Or accessibility tools that change the styling of the site? Or password managers that inject auto fill buttons? Or addons like RES that add features like previously viewed posts or times you've upvoted a user?

Injecting ads is the same idea, you're removing features you dislike and adding features you do. The unethical part is profiting from sites, which is why those profits should be shared with those sites. I think there's a good case to be made that sites, browsers, and users can all make more with this method and without violating user privacy (the advertiser doesn't need to know anything about you specifically, it just needs to know that the browser can place ads effectively). All data can stay on your local machine and never sent to the browser vendor, website owners, or advertisers.

If Brave got that to work, I'd consider it. I'd prefer it to be an addon to my browser instead. Here's how I'd prefer it to work:

1. I install an open source, auditable extension that tracks my browsing history locally to serve relevant ads
2. Sites sign up for the program and provide a tracking key that only tracks that website (unique per site, not part session/user)
3. Once I hit some amount of ad views on a given site in a given day, ads go away; my browser is 100% in control of that
4. Profits go to an open, auditable service that distributes a portion to sites, the addon vendor, and users who opt in (with anymore crypto wallets); if users opt out, those profits are donated to a charity instead (again, publicly auditable)

This way, the user:s privacy isn't violated, sites make a profit, the addon maintainer gets paid (ideally a nonprofit org), and users can get some pocket change as well. Everything would be auditable, so nobody can pull a fast one without getting caught.