The Polkadot blockchain is a multi-chain blockchain that is designed to bundle multiple chains together so that they can be executed in parallel. The goal is for every block on the Polkadot blockchain to contain multiple blocks from other chains. This will enable the network to contain the transaction information from multiple chains and dramatically increase the overall interoperability between different blockchain networks. Polkadot was created by the Web3 Foundation, which is led by Gavin Wood, one of the founders of Ethereum. Polkadot is their flagship project, and aims to solve the issues in the blockchain ecosystem related to disjointed governance and interoperability.
Ontology is a network designed to be operated across multiple blockchains. Its main focus revolves around trust issues, and it provides identity verification and reputation management capabilities. Ontology's goal is to be a platform for decentralized trust systems in businesses. Their distributed network is set up to facilitate cooperation between different projects in a trust ecosystem. Ontology's framework allows users to customize different public blockchains for different applications. Ontology has a two-token structure. ONT is the utility token of the network that can be used to generate Ontology Gas (ONG). Ontology has an innovative consensus mechanism called Verifiable Byzantine Fault Tolerance (VBFT). It combines elements of Proof-of-Stake (PoS), VRF (Verifiable Number Function), and Byzantine Fault Tolerance (BFT). The VBFT consensus mechanism will select nodes that meet certain conditions, and will verify transactions.