Websites that have a shopping cart or checkout page, either using a known ecommerce platform or a custom solution.
Firebase is a Google-backed application development software that enables developers to develop iOS, Android and Web apps.
Handlebars is a JavaScript library used to create reusable webpage templates.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Underscore.js is a JavaScript library which provides utility functions for common programming tasks. It is comparable to features provided by Prototype.js and the Ruby language, but opts for a functional programming design instead of extending object prototypes.
Varnish is a reverse caching proxy.