I think you're misunderstanding the nature of what I'm proposing. You don't sign a hash of the URL or the page. You sign a URL of the content. If the content c

I think you're misunderstanding the nature of what I'm proposing. You don't sign a hash of the URL or the page. You sign a URL of the content. If the content changes, your signed hash will no longer match, and the like no longer validates, which is exactly the point--your like isn't intended to apply to all future things the page owner could possibly put on that page, it's intended to apply only to the content that is there. And personally, I'd never intentionally like an ad anyway. In general, ads causing things to lose all likes if they inject them into the content would be a good thing, because it would force advertisers to differentiate dynamic ads from content. EDIT: I see you edited to clarify your other post, so my post here doesn't really apply any more. I've responded to that post directly.