A proposal:
Advertising that will only appear if someone comes from a particular country.
Advantage: On the one hand it is much cheaper for the advertiser. His ads are popping up less frequently. He can apply target groups.
The second advantage: you can require at least 50% -100% more for countries advertising. It's still cheaper for the advertiser.
And quite general advantage: At the local level, there is more trust and it will be better developed business ideas. (Think global, act local)
Terrible idea I my opinion , when you have an online shop you want to be noticed all around the world since there is no physical barriers to buy the item and pay the transaction ... instead that I will suggest that if a banner comes in other language than English it should be only shown to people that use that language on his browsers .
Country filters would only be an option, not mandatory.
Of course publishers could still choose "worldwide" as an option.
Language could be another optional filter.
Awesome !