A set of 3 possibe properties for a good ID/naming system to have: security, decentralisation, and human-meaning/memorability. Conjectured that no single system can achieve all 3 by Zooko Wilcox-O'Hearn (just found out they're also one of the creators of Zcash).
eg. Bitcoin/nostr addresses, which are secure and decentralised but rarely memorable or meaningful, and DNS names, which can be secure and meaningful but quite centrally controlled.