Chat protocols play a crucial role in driving product adoption, user engagement, and retention. There are various chat protocols to consider when implementing chat in an application, each addressing different aspects of the problem with varying degrees of thoroughness. Some popular protocols include WebSocket, WebRTC, MQTT, XMPP, AMPQ, Matrix, Server Sent Events, and IRC. When choosing a protocol, factors such as how clients connect, data types supported, reliability, latency, scalability, and security should be considered.