How is interest earned?

When a user deposits, the Poof smart contract wraps those tokens into interest-bearing versions. These interest-bearing versions should monotonically be worth more of the underlying token over time. E.g. Today, 1 token = 1000 wrapped tokens. In 1 year, 1 token = 500 wrapped tokens. This allows users to earn interest while owning a constant # of tokens in the smart contracts

What are relayers?

Relayers are servers that anyone can run. Relayers receive withdraw and borrow transactions from users and execute them on those user's behalf. Users pay two fees to these relayers that come out of their hidden balance: (1) A % of the amount they are withdrawing / borrowing and (2) The amount of gas the relayer anticipates on spending. By having relayers, users can send funds into completely empty wallets