As a user/contributor, you can participate in the projects built on top of the protocol, buying some products or adding liquidity to a pool. Please note that some projects are subject to restricted access. As a developer, you can build your own projects on top of the protocol; for example, one team created a market for decentralized analogues of futures contracts on Olive oil. Alternatively, you may find a vulnerability and participate in the Opium bug bounty program. As a specialist in some field, you can contribute to project development. For example, this documentation is open-source, so if you see a way to improve it, you can make a submission. As a financial engineer, you can build a bot to arbitrage between products and protocols.