I've been thinking about that. Can we leverage proof of work to sign meaningful content? I'm thinking of a voluntary HTML tag, containing a cryptographic signature, that has to match the page content, to be eligible for placement in a "spam-free" search engine.

For an actual creator, a few seconds of publishing delay is nothing. To an army of spam bots, having to waste time and energy calculating hashes could be crippling.

What if we apply this to every link on the page?