At the risk of sounding like a cryptobro, could we have something like a proof of work or a web of trust for posts? So you could vote on if you think something

At the risk of sounding like a cryptobro, could we have something like a proof of work or a web of trust for posts? So you could vote on if you think something was authored by a human? At least the cost for a spam post would not be virtually zero like now. I'm sure people have thought about this, are there any viable solutions?