Tezos is a smart contract platform with its own blockchain and a native token (Tezos, XTZ). The governance is performed via Proof-of-Stake algorithm. It means that stakeholders (those who own at least 10,000 XTZ) vote for changes in the protocol. These validators ("bakers") get rewards for the performance of validation. The rewards are generated via inflation. Those who delegate their XTZ to bakers can earn, too.
Tezos has a built-in "self-amendment" mechanism which makes it possible to shape the network without having to make forks. It keeps the community united and makes development process easier.
Arweave aims to make information permanence sustainable. Arweave describes itself as a new type of storage that backs data with sustainable and perpetual endowments, allowing users and developers to store data forever. As a collectively owned hard drive that never forgets, Arweave aims to allow users to remember and preserve valuable information, apps, and history indefinitely. By preserving history, it prevents others from rewriting it.