I think the issue there is getting a scheme that has the asymmetric validation. And you want the results of a crawl. You could merkle up the different pages yo

I think the issue there is getting a scheme that has the asymmetric validation. And you want the results of a crawl. You could merkle up the different pages you've crawled, and combine with a part of your public key to get a unique hash. But, the question is why would someone pay for it?