Ethereum Classic

People who hold Ether from before the hard-fork have a possible balance of ETH in addition to an equal amount of Classic Ether (ETC). Exchanges that hold customer funds are also in control of the ETC in proportional quantity to their ETH holdings prior to the hard-fork. Users at most ETH exchanges are demanding their ETC be made available to them.  As of 11 August 2016, both Ethers are actively traded.  The ETC chain did a hard fork to adjust the internal pricing for running various op codes on the Ethereum Virtual Machine (EVM) on 25 October 2016, similar to the hard fork the ETH chain did a week earlier. The goal was to more rationaly price various compute-intensive and external reference commands to reduce the incentive for spammers who had conducted a month-long distributed denial-of-service attack on the ETC network.