A pretty efficient algorithm for content discovery/filtering for any social network.
https://github.com/pippellia-btc/The-Problem-of-Spam/
On my old pc it can compute over the whole Nostr network in less than 10m
nostr:npub1xdtducdnjerex88gkg2qk2atsdlqsyxqaag4h05jmcpyspqt30wscmntxy
