Christoffer Klemming, a former Google PMM, used his programming skills to develop an SMS notification system for businesses using AngularJS, Firebase, and Twilio. He created Waitwhile, a service that allows customers to receive texts when they're ready to be served at salons or restaurants. Christoffer shares his tutorial on how to build SMS notifications with AngularJS and Firebase in eight steps, including setting up Firebase, Twilio, and Zapier integrations. The system can be personalized and secured with Firebase security rules, and also supports two-way SMS functionality.