Phoenix LiveView is an experimental feature allowing developers to create rich, real-time user experiences with server-rendered HTML. It can be used in conjunction with Mux Live Streaming and Elixir programming language. The example app "Snitch" demonstrates how LiveView handles webhooks from Mux by re-rendering on the server side and pushing changes to the client, eliminating the need for websockets or polling. This feature is useful in applications that require real-time updates and can be used across various industries.