Ethereum is a decentralized platform that runs smart contracts: applications that run exactly as programmed without any possibility of fraud or third party interference.
These apps run on a custom built blockchain, an enormously powerful shared global infrastructure that can move value around and represent the ownership of property. This enables developers to create markets, store registries of debts or promises, move funds in accordance with instructions given long in the past (like a will or a futures contract) and many other things that have not been invented yet, all without a middleman or counterparty risk.
The project was bootstrapped via an ether presale in August 2014 by fans all around the world. It is developed by the Ethereum Foundation, a Swiss non-profit, with contributions from great minds across the globe.
The Ethereum protocol could be used to build Decentralized Autonomous Organizations (DAO). A DAO is an organization with no central authority or control.
A DAO is owned by everyone who purchases tokens, but instead of each token equating to equity shares & ownership, tokens act as contributions that give people voting rights.
DAOs are organizations that exist on the Internet and are not subject to geographic borders or restrictions. The code for a DAO is stored on every computer that participates in the network and anyone can join or leave a DAO at any time.
Decisions are made democratically with everyone having an equal say.
A key feature of Ethereum is that it enables developers to create new types of applications that were not possible before. These are called Decentralized Applications or DApps for short.
A DApp can have its own blockchain (like Bitcoin) or it can use Ethereum’s blockchain as its foundation (like Augur).
What makes Ethereum different from Bitcoin? Both Bitcoin and Ethereum are decentralized protocols running on top of a network of computers that anyone can access and use. However, there are significant technical differences between the two. For one, they use different consensus mechanisms to achieve distributed consensus; Bitcoin uses Proof-of-Work (PoW) while Ethereum uses Proof-of-Stake (PoS). PoW requires miners to solve computationally intensive puzzles in order to validate transactions and add them to the blockchain; in return they are rewarded with cryptocurrency. PoS does not require mining in order to validate transactions; rather,validators stake their cryptocurrency holdings in order to earn rewards for each block they validate.
PoS is more energy efficient than PoW since it does not require miners to expend large amounts of electricity in order to validate transactions and add them to the blockchain.
Another key difference between Bitcoin and Ethereum is their purpose; Bitcoin was designed as a peer-to-peer electronic cash system while Ethereum was developed as a platform which enables Decentralized Applications and Smart Contracts to be built and run without any third party interference.
Ethereum also has its own cryptocurrency called “Ether” which is used to pay for transaction fees and services on the network; this is similar to how Bitcoin uses its own currency “BTC” for transaction fees on its network.
So in summary, while both Bitcoin and Ethereum are decentralized protocols running on top of a network of computers which anyone can access and use, there are significant technical differences between the two; chiefly their purpose, consensus mechanisms and currency used for transaction fees.