PoW doesn't address spam. Sorry. Spammers have more PoW **per message** than real users.
nostr:npub1xtscya34g58tk0z605fvr788k263gsu6cy9x0mhnm87echrgufzsevkk5s, could I try and bring https://github.com/damus-io/damus/pull/172/ up to date (probably as a new pull request) so that Damus sends messages with PoW automatically? I know you said that you think Lightning is a better filter, but every single person sending notes on Nostr can calculate PoW since they obviously already have a computer whereas the same is not true for Lightning. If Damus leads the charge on this and if we can get nostr:npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z on board we could make PoW default on notes which could almost completely solve the spam problem.
Discussion
What exactly do you mean by that? A real user is usually sending less than a few dozen notes per day. Spammers are sending thousands. A spammer would therefore have to have far, far, more compute than a real user to spam. I'm not saying that a spammer couldn't do this but that PoW would raise the cost per note above what a spammer can hope to make from that note.
This ^^ I think at the end PoW NIP does not address anything or am i missing something?