Waltz

This uses Clef (https://getclef.com/ - which was featured on Product Hunt itself a whopping 2 years ago). Clef lets you use your phone to log into sites securely, and Waltz is a magical Chrome plugin that uses Clef to allow you to login to Facebook, Twitter, etc.

DIdn't get the idea, How Waltz works ?

Waltz is great. It allows you to log in to sites with your phone (instead of having to type in your password).