The Cardano blockchain is a 3rd generation blockchain platform that was designed with a collaborative peer-to-peer review system, It aims to improve upon prior blockchain systems to enable larger and more sustainable uses of the technology.
Cardano was built with a governance model that is based on collaboration. This allows the platform to evolve quickly and adapt to the changing needs of its users. Unlike many other blockchain projects, it also installed a treasury system to fund the ongoing development needs that may arise as it moves forward.
The Cardano blockchain uses a unique proof of stake algorithm called Ouroboros and has a protocol that consists of two layers, a settlement layer and a control layer. The settlement layer is designed to perform accounting functions, while the control layer is tasked with running smart contracts. The platform tries to balance the privacy concerns of users with the requirements of regulators in an effective way.
Cardano uses the Haskell programming language and is fueled by the ADA coin

Chain is a blockchain software company that creates blockchain-based systems for financial institutions and major companies. They've developed blockchain solutions for companies like Nasdaq, Visa, and Citigroup, as well as a variety of crytpocurrencies. Chain has been successful in incorporating distributed ledger technology in very large and influential companies. Their focus is on using the core innovations of blockchain to improve existing systems. Chain uses blockchain as a software tool that can be applied where it is important for services or product to have more trust, or to build a network without an intermediary

Holo is a decentralized hosting provider that is built on top of Holochain. DApps can be set up and deployed with Holo hosting, as a decentralized alternative to Amazon Web Services, or other centralized hosting solutions.
Holochain is a protocol for creating decentralized Apps and is different from blockchain protocols in several ways. The main difference being that Holochain takes an agent-centric approach to their consensus mechanism, and has a different approach to validating value transfers.
The HOT token is used for paying for hosting services on Holo, and users can be paid for offering their computing resources.