I’ve said it before but my pow32 Is an experiment
Discussion
pow32 relay
Yeh yeh but it’s a good idea for the spam/bot problem. There’s definitely merit there in my mind. :)
(MIned keys + blocking spammers by key + (IMHO) blocking events that are not recent) seems like a good strategy as long as there is no cryptographic issue with narrowing the keyspace subtantially. I'd love for a cryptographer to let us know, because if it's okay, then I think this is a really good idea.