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.

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

Emercoin is a blockchain-based development platform. It has developed a range of easy-to-use dSDKs (Decentralized Software Development Kits) that can be used to more easily build DApps. This set of software development tools allow the creation of blockchain-based software and services.
Emercoin's dSDKs have been implemented in several innovative DApps and provide developers with solutions for a variety of functionalities. Some of the dSDK's that Emercoin offers are specifically geared for decentralized DNS, SSH, SSL, and DPO solutions.
Emercoin has a hybrid consensus mechanism that combines elements of Proof-of-Stake (PoS) with a Proof-of-Work (PoW) algorithm that is merge-mined with Bitcoin. The network is powered by the EMC coin.