cdnjs is a free distributed JS library delivery service.
Font Awesome is a font and icon toolkit based on CSS and Less.
Google Analytics is a free web analytics service that tracks and reports website traffic.
Google Hosted Libraries is a stable, reliable, high-speed, globally available content distribution network for the most popular, open-source JavaScript libraries.
Heroku is a cloud platform as a service (PaaS) supporting several programming languages.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
Progressive Web Apps (PWAs) are web apps built and enhanced with modern APIs to deliver enhanced capabilities, reliability, and installability while reaching anyone, anywhere, on any device, all with a single codebase.
RequireJS is a JavaScript library and file loader which manages the dependencies between JavaScript files and in modular programming.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.