Ethereum (ETH)
Ethereum is a crypto platform. Although it has its own token (called Ether), other cryptoasset projects are built upon the Ethereum blockchain, and have their own tokens. At the present time, the majority of these other projects have tokens based upon a standard called the ERC20 standard, and thus are often referred to as ERC20 tokens. Examples of ERC20 tokens include DNT, GNT, OMG, and many others. Ethereum is commonly used as a cryptocurrency, although that was not its main intention. It was designed specifically to be a simple framework on which other blockchain projects could be easily built. Ethereum is the crypto which is the second most commonly used in trading pairs, after Bitcoin. Many people use Ethereum when purchasing altcoins, because it is much faster and cheaper to move Ethereum from a fiat gateway exchange to other exchanges that specialize in altcoins. Ethereum is notable for its ability to handle smart contracts.
Mining/Staking
Ethereum currently uses a Proof of Work (mining) consensus system as of early 2018, however, it is actively trying to transition to a more environmentally friendly Proof of Stake system.
Development Team
The main developer behind the Ethereum project is Vitalik Buterin, a Russian-Canadian developer and figurehead for the project. Vitalik is also probably the most prominent and notable persona in blockchain technology today.
Criticisms, Caveats, and Competitors
One of Ethereum's biggest criticisms is that smart contracts have to be written in a specific coding language called Solidity, which a lot of coders have to learn specifically for use with Ethereum development.
Additional Resources
The project's main website: https://www.ethereum.org
Link to Wikipedia Page: https://en.wikipedia.org/wiki/Ethereum
Link to Reddit Community: https://www.reddit.com/r/ethereum
Link to Twitter account: https://twitter.com/ethereumproject
Link to Team information: https://www.ethereum.org/foundation
Link to data on Live Coin Watch: https://www.livecoinwatch.com/coins/ETH
Whitepaper: https://github.com/ethereum/wiki/wiki/White-Paper