The DAO Hack
A 2016 exploit that drained millions from a flagship Ethereum project and forced a contentious hard fork.
The DAO was a crowd-funded investment fund built on Ethereum, holding over 150 million dollars in ether at its peak. In June 2016 an attacker used a reentrancy bug to siphon roughly a third of it.
Ethereum's community voted to reverse the theft with a hard fork, restoring the funds. Those who refused, arguing the chain should be immutable, kept the original ledger as Ethereum Classic. The split still shapes debates about whether code is truly law.
Related terms
An organization governed by token holders voting on-chain, where rules and treasury live in smart contracts instead of a boardroom.
Reentrancy AttackAn exploit where a contract is called back mid-execution, draining funds before its balances update.
Hard ForkA backward-incompatible rule change that forces every node to upgrade, sometimes splitting one chain into two.
Vitalik ButerinThe Russian-Canadian programmer who proposed Ethereum in 2013 and remains its most influential public figure.