Ethereum Classic (ETC) is the original Ethereum blockchain that kept going after a 2016 split. When a major hack drained a big project on Ethereum, most of the community chose to reverse it with a code change (creating today's Ethereum, ETH); a minority refused, arguing 'code is law' and that the chain should never be altered — they kept the untouched original chain, which became Ethereum Classic. ETC still runs proof-of-work mining (like Bitcoin), whereas Ethereum switched to proof-of-stake in 2022. It has a hard-capped supply (about 210 million, unlike ETH's uncapped model), giving it a 'sound money' pitch. ETC is used for fees, mining rewards and securing the network.
Where it stands today: ETC found an unexpected purpose after Ethereum's 2022 switch to proof-of-stake — it absorbed a wave of displaced Ethereum miners, becoming the largest proof-of-work smart-contract chain and hugely boosting its mining security (it now controls the vast majority of its mining algorithm's power, fixing the '51% attack' vulnerability that plagued it years ago). An upgrade ('Olympia', targeted for late 2026) aims to add modern fee mechanics and on-chain governance without touching its fixed supply. But ETC has very little actual app activity or developer ecosystem — it's more a symbol (immutable, capped, PoW) and a miner's chain than a thriving platform. So today it's a secure, principled, scarce coin that survives mostly on ideology and mining, not on usage.