Chromia is a relational blockchain platform that is designed to be both a blockchain and a relational database. Chromia was created by a Swedish development company called ChromaWay, with the intention of combining the advantages of a blockchain's transparency with the benefits of a relational database system, such as data independence and reduced redundancy.

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.