IIRC Opera had it years ago. Maybe even before there was Firefox.
they had ads but only in the free version, if you bought opera there were no ads.
Well… of sorts. The default set on Speed Dial were (and are) sold, which you can easily construe as adverts.
That's not what they did. They embedded targeted ads that respected your privacy, by having all targeting done client side and not sending information about you back to the server.
That the general public doesn't care about that is one thing, that all the people crtizising them here don't seem to care is another.