What if we could resolve every domain to 0.0.0.0 by default at the start. When visiting a website manually through the browser's URL bar it would automatically be whitelisted. Clicking links would also whitelist the domain of the link only. Sure you'd have to occasionally allow some 3rd party domains as well. Guess it would be cumbersome at first but after a while it would be pretty stable and wouldn't require much extra attention.