What is Ethereum?
Ethereum is an open-source, public, blockchain-based distributed computing platform featuring smart contract (scripting) functionality. It provides a decentralized Turing-complete virtual machine, the Ethereum Virtual Machine (EVM), which can execute scripts using an international network of public nodes.
Ethereum was proposed in late 2013 by Vitalik Buterin, a cryptocurrency researcher and programmer. Development was funded by an online crowdsale during July–August 2014. The system went live on 30 July 2015.
Purpose of the tokenThe ethereum network provides a cryptocurrency token called “ether”, which can be transferred between accounts and used to compensate participant nodes for computations performed. “Gas”, an internal transaction pricing mechanism, is used to mitigate spam and allocate resources on the network.
The token is used to pay for the execution of "smart contracts" which are little programs run on the Ethereum network which most often are programs designed to execute a value transfer between two or more parties. Ether can also be used as a currency to pay one another.