Compound (COMP) is an ERC-20 asset that powers the community governance of the Compound protocol; COMP token-holders and their delegates debate, propose, and vote on changes to the protocol. By placing COMP directly into the hands of users and applications, an increasingly large ecosystem will be able to upgrade the protocol and will be incentivized to collectively steward the protocol into the future with good governance.
Project Serum describes itself as a functional decentralized exchange with trustless cross-chain trading, at the speed and price that customers want. Despite living natively on Solana, it will be interoperable with Ethereum.