If you use Chrome, Google can use a network protocol for tracking and ad delivery that can't be seen or blocked by extensions. TL;DR: You really shouldn't use a web browser made by an ad company.
"AdBlock Plus, uBlock Origin, and other extensions cannot block QUIC requests. Recommended best practice is to disable QUIC from the chrome://flags/ URL."
@ocdtrekkie to be fair, though; there's no better testing ground for what a new protocol can take than serving ads. It would be nice of them to be a bit more open about it and offer opt-outs (and honour existing opt-outs).