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.

Lisk is a blockchain-based platform that allows developers to build and publish their own applications. Lisk uses sidechain development kits, that are written in Javascript, to enable users to create their own blockchain applications according to their needs. Each decentralized App runs on its own sidechain that can be customized, and is connected to the Lisk blockchain, which has a Delegated Proof-of-Stake (dPoS) consensus mechanism. The Lisk network is powered by the LSK coin.

ARK, which is a fork of Lisk, is developing an interconnected blockchain ecosystem that will make it easier for users to develop their own blockchains. Ark emphasizes interoperability and usability. Their moto is “Point.Click.Blockchain” and their goal is to allow for easy deployment of DApps. Ark's "push button blockchains" can be easily created with minimal programming knowledge. Ark also hopes to encourage adoption by developers by accommodating 18 different programming languages.
Ark has a delegated Proof-of-Stake (dPoS) consensus mechanism. Their governance model allows users to vote for delegates that secure the network. The top 51 delegates voluntarily share there tokens with their voters.
Ark contract execution service (ACES) connects ARK with other blockchains and will enable exchanges of value between them.