WebSockets allow for bidirectional communication between a client and server over a single TCP connection. They provide lower latency and overhead than traditional HTTP requests which require a new connection for each request. The talk demonstrated how to use WebSockets with JavaScript on the client and event-driven servers like Node.js on the server. While browser support is still limited and the specification is in flux, WebSockets offer a way to build real-time applications without hacks like long-polling that HTTP requires.