Ethereum is a decentralized platform that allows the creation of intelligent contracts agreements between peers. Any developer can create and publish distributed applications that perform smart contracts.
After a bifurcation of the block chain in July 2016, there are two active Ethereum lines: Ethereum and Ethereum Classic.
The initial purpose of the Ethereum project is to decentralize the web by introducing four components as part of its Web 3.0 roadmap: publishing static content, dynamic messaging, reliable transactions and an integrated and functional user interface. These components are designed to replace some aspects of the Web experience we take for granted today, but doing so in a completely decentralized and anonymous way.
Ethereum works in a decentralized way through a virtual machine called Ethereum Virtual Machine (EVM). This machine runs an intermediate code or bytecode which is a mixture of LISP, assembler and bitcoin script.
Programs that perform smart contracts are written in full Turing-type high-level programming languages, such as Serpent or Solidity, which follow the contract design methodology to create smart contracts.
Ethereum uses as internal currency the ether, the decentralized criptomoneda underlying it that serves to execute the contracts of the same one. In this regard, Ethereum is not like most existing crypto-currencies, since it is not only a network to reflect transactions of monetary value, but is a network for the feeding of contracts based on Ethereum. These open source contracts can be used to securely execute a wide variety of services, including voting systems, financial exchanges, micromanaging platforms, intellectual property, and autonomous decentralized organizations.
An ether is divided into smaller units called finney, szabo, shannon, babbage, lovelace and wei. Each unit equals a thousand times the next smaller unit, so 1000 finneys are a 1 ether, 1000 szabos are a finney, and so on.