Ethereum is a decentralized platform that runs smart contracts: applications that run exactly as programmed without any possibility of downtime, censorship, fraud or third party interference.
This is step-by-step guide, how to setup testnet Ethereum network.
We'll setup ethereum testnet node in the docker container and write ruby json-rpc client. The difference between ethereum(Frontier) and testnet ethereum(Ropsten) networks is that the testnet used for development. The genesis block on the testnet was set with a very low difficulty so anyone can do minning. The coins mained in the testnet have no values. You can request some coins on the facuet or trying to mine it.