Twilio Functions` is a serverless runtime that allows developers to handle webhooks from programmable communication APIs like Twilio. The article demonstrates how to create a `Twilio Function` in ClojureScript using the `Shadow CLJS` compiler and the `Twilio CLI`. It covers the setup, configuration, and deployment of the function, as well as adding functionality such as responding to SMS with random quotes from Rich Hickey's collection. The article provides detailed instructions on how to build a functional Twilio Function in ClojureScript using Shadow CLJS and the Twilio CLI.