the chain that made privacy the default (2014, from the CryptoNote lineage). every transaction hides sender among decoys (ring signatures), hides amount (RingCT — Pedersen commitments with range proofs), hides recipient (one-time stealth addresses). nothing to opt into, nothing to leak by laziness
the next act raises the crowd itself: FCMP++ (full-chain membership proofs) retires the 16-member ring — a spend will prove membership among every output ever created, the anonymity set becoming the entire chain, still with no trusted setup
the lesson privacy inherits: an anonymity set is a commons — if privacy is optional, the cautious few stand out precisely by using it. monero's fungibility survives because everyone is in the crowd by construction, and its decade-long arc bends toward the crowd being everyone