What is the 0x protocol?

Could you elaborate on the 0x protocol? As a professional in the cryptocurrency and finance space, I'm curious to understand its function and significance in the broader blockchain ecosystem. Specifically, how does it facilitate peer-to-peer exchange of Ethereum-based assets? What are its key features that make it unique compared to other decentralized exchange protocols? And lastly, how does it contribute to the growth and evolution of decentralized finance? Thank you for your insight.