Ethereum

Ethereum is a blockchain, a decentralised network created by Vitalik Buterin. Ethereum is often described as a decentralised world computer because it allows developers to create decentralised applications that run on a global network of computers.

Here are some of the key characteristics of the Ethereum blockchain:

• Smart contracts: Smart contracts are self-executing contracts that contain the terms of the agreement written into the code and can run off the Ethereum blockchain, hence accruing fees for the blockchain. They limit the need for intermediaries and can enable tamper-proof transactions. 
• Decentralised applications (dApps): These applications can run on the Ethereum blockchain. DApps have many use cases, including decentralised finance (DeFi), gaming, supply chains, and more.
• NFTs (Non-Fungible Tokens): Ethereum is the main platform for creating and trading NFTs, which are unique digital assets representing ownership of art, collectables, and more. 

Ethereum was created in 2013, but the network went live a few months later, in July 2015.

Ether is the native cryptocurrency of the Ethereum blockchain. It’s a digital currency used to facilitate transactions and smart contract executions on Ethereum. It’s also a popular cryptocurrency to grow and diversify portfolios, and today ranks as the second largest cryptocurrency by market cap. So, when people talk about “Ethereum”, they are really referring to the cryptocurrency Ether.

The Ethereum blockchain currently relies on the proof-of-stake consensus model. In this consensus model, validators create new blocks and validate transactions. They are chosen based on the amount of cryptocurrency they hold and how much they “stake” as collateral.

Interestingly, Ethereum was previously using the proof-of-work consensus model but switched over environmental concerns to proof-of-stake, which is supposedly less energy-consuming.