[fiatjaf]

No. Anyone can run the same page on a different domain. The only case in which you aren't satisfied with this possibility is the one in which you truly want to place an add on the page.

[sturmeh]

Why would anyone else run the ad?

[rtpg]

decentralized ad network? People can buy slots, get credits for showing it to users?

Not sure how that works for getting credits for display but something in that space would be interesting