Ethereum Classic is one of two currencies that use the Ethereum blockchain, with Ethereum or Ether (ETH) being the other one. Ethereum Classic is an open-source, public, blockchain-based distributed computing platform. The currency emerged after the original Ethereum platform forked into two versions, including Ethereum Classic (ETC) and Ethereum (ETH). ETC was officially released after the DAO hard fork in 2016, which occurred one year after the launch of Ethereum. Like Ethereum, Ethereum Classic provides a decentralized, Turing-complete virtual machine called the Ethereum Virtual Machine (EVM), as well as smart contract functionality.
Today, you can buy Ethereum Classic (ETC), known as "classic Ether" on most cryptocurrency exchanges, and you can store it in a wallet, just like you would hold Ethereum and other currencies.
ETC uses gas, an internal transaction pricing mechanism, to prevent spam on the network and allocate resources proportionally to the incentive offered by the request.
Prior to the fork, there was one version of Ethereum. It was called Ethereum. Then, there was a disagreement on how to handle the situation created by the DAO.
In May 2016, the DAO, a venture capital fund, was built on Ethereum and raised an enormous amount of money to the tune of $168 million to invest in smart contract development. With this, investors recognized the potential of smart contracts, and believed the DAO, which stands for "Decentralized Autonomous Organization" was one of the best chances for smart contracts to reach their full potential.
However that same month, a paper was released explaining security vulnerabilities in the DAO. It had indicated that those security vulnerabilities could allow the money to be stolen. And sure enough, just one month later, in June, a hacker stole 3.6 million Ether (equivalent to about $50 million at the time) from the DAO. The money was taken from the DAO's accounts and moved to another account without the owners' consent, which was one of the notable vulnerabilities warned about in the May 2016 paper.
Interestingly however, the hacker's $50 million fund wasn't immediately withdrawn, and it was still sitting in the child DAO, because fortunately the hacker couldn't access the funds, since the DAO's smart contract had stated that any invested money was unable to be removed for 28 days. Still the DAO had lost nearly one third of its investments, triggering the community and investors alike to talk about how to proceed.
There were two approaches:
Part of the Ethereum community wanted to "roll back" the blockchain, move the Ether taken in the exploit to a new smart contract, and allow the Ether to be restored to the owners from whom it had been taken. This would effectively roll back the Ethereum blockchain through a soft fork, which meant that investors could keep their stolen funds.
Another part of the Ethereum community believed in the immutability of the blockchain; rolling back the blockchain was a fundamental violation of that immutability. Hence, members of the Ethereum community rejected the proposed soft fork based on this principle.
The second group, ie the group that believed in immutability, rejected the hard fork and continued to use the unforked version of Ethereum, and this unforked version of Ethereum became known as Ethereum Classic, while the hard fork version of Ethereum is known simply as Ethereum today.
The Ethereum Soft Fork Versus The Hard Fork
The majority of Ethereum users agreed that a soft fork was the best way to proceed. A soft fork is like a backwards-compatible software update, and users weren't forced to upgrade. Updated users could still interact with non-updated users.
However, a soft fork has a major problem, because implementing a soft fork would have resulted in a Denial of Service (DoS) attack vector. Typically, Ethereum's network is protected from DoS attacks (which essentially involve flooding the network) due to the presence of Gas as a transaction cost.
A hard fork, unlike a soft fork, is not backwards compatible. Once a hard fork is used, there's no going back. Anybody who isn't using the upgraded version of the blockchain will not be able to access new updates or interact with new users on the system. For all intents and purposes, it's like you're using two different currencies, where they just happen to be built on the same original blockchain.
Ultimately, all of Ethereum's major players, including founders Vitalik Buterin and Gavin Wood moved onto the new chain. However, Ethereum Classic continues to have support, mostly from those who believe in the immutability of blockchain technology above all else. One of ETC's biggest supporters is Barry Silbert, the CEO of Grayscale. Silbert has been a big backer for the digital coin, which grew in value more than 90 times in 2017, before falling back within a broader selloff across the cryptocurrency markets. His successful bet on Ethereum Classic prompted some of these detractors to decry his postings on price and attempt to divert enthusiasm for the new coin because it raises concerns over possible price manipulation.
The main problem with Ethereum Classic is that it's not backwards compatible with the Ethereum hard fork, hence all of Ethereum's main developers and founding team have moved onto the forked version of Ethereum. Irrespective, the ETC project counts the building of a larger team as one of the milestones achieved in 2017: The price of Ethereum Classic has fluctuated over the years. At launch, after the hard fork, the price of Ethereum Classic fluctuated between $0.75 and $3 per token before dropping to a range of $1 to $2 for the remainder of 2016 and early 2017. It has since risen to $41 before dropping back to about $36 in February 2018.
The coin has a market cap of around $1.5 billion, making it one of the top 5 or 10 largest cryptocurrencies in the world. Furthermore ETC is still in active development. Of course neither ETH nor ETC are perfect currencies. However, truth be told, ETH has far greater support - and a much larger market cap. Yet despite its low price, Ethereum Classic remains an important digital asset with a strong community.