The article describes how to build a Shazam-like song identifier phone service using Twilio Voice and SMS, along with JavaScript. The service will record an incoming call for 5 seconds, identify the song using the Shazam API, and then send an SMS with the song information to the caller. If the song is not detected, it will record and identify the next 5 seconds of the song. The service also includes a few upgrades such as improved audio quality and caching of recording URLs.