Before Ethereum, blockchain technology provided an immutable ledger to track the flow of value, and cryptocurrencies (tokens) represented that value. When Ethereum emerged, it introduced a sort of "operating system" (OS) that runs on top of the blockchain. This OS supports a multitude of different types of tokens and smart contracts that allow decentralized applications (dAPPS) to interact with a new global financial backbone. It is an immutable, secure, decentralized network to exchange tokens representing a plethora of value propositions.