Bitcoin is the first digital currency based on blockchain. It solved the double-spending problem and enabled peer-to-peer transactions on a large scale. Bitcoin was designed to work as a trustless digital currency that would function without government oversight or a central bank.
Bitcoin was developed by Satoshi Nakamoto, whose identity has never been confirmed and has become the subject of great intrigue. Bitcoin builds upon on other cryptographic and digital currency projects that came before it, but its use of blockchain made it more viable. Nakamoto originally released his white paper and open-source software on a cryptography forum. He mined the first block of the Bitcoin chain, called the genesis block in January 2009.
Bitcoins are created as a reward for a process known as mining. One of the core innovations of Bitcoin, is its consensus algorithm, which creates an incentive system that rewards miners for confirming transactions.
Hal Finney, who developed the first reusable proof-of-work system (RPOW), several years before, was the first Bitcoin adopter and received the first bitcoin transaction ever recorded on its blockchain.

Ethereum is a blockchain-based computing platform and operating system whose core innovation is enabling smart contracts. Ethereum's smart contract functionality, and versatile scripting language, have made it the most popular network for creating decentralized applications. What makes Ethereum different from Bitcoin is that its primary purpose is to serve as a general purpose blockchain for creating DApps, and not as a payment network. Ethereum was created by Vitalik Buterin. It was launched in July 2015 and has become one of the most important blockchain platforms in the industry. Ether is the native currency of the Ethereum blockchain and can can be used as a transfer of value, as well as a form of compensation for mining. The Ethereum Virtual Machine (EVM) executes scripts using a network of public nodes. "Gas" is used as an internal transaction pricing mechanism that decides how resources are used on the network.

PIRL is a community based blockchain project focused on making cryptocurrencies more accessible. It was the first blockchain to introduce an Ethash-based masternode. Their goal is to develop a comprehensive DApps hosting infrastructure that will be easy to use. Their Poseidon platform is designed to be an on ramp for users without any technical knowledge. PIRL's multi-tiered masternode network has an ASIC-resistant Proof-of-Work (PoW) consensus mechanism, and is powered by the PIRL coin. The company plans on developing features, such as: decentralized file storage, messaging, and escrow services for payments.