Bootstrap is a free and open-source CSS framework directed at responsive, mobile-first front-end web development. It contains CSS and JavaScript-based design templates for typography, forms, buttons, navigation, and other interface components.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
jQuery CDN is a way to include jQuery in your website without actually downloading and keeping it your website's folder.
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.
Open Graph is a protocol that is used to integrate any web page into the social graph.
PHP is a general-purpose scripting language used for web development.
RequireJS is a JavaScript library and file loader which manages the dependencies between JavaScript files and in modular programming.
Typekit is an online service which offers a subscription library of fonts.
Yii is an open-source, object-oriented, component-based MVC PHP web application framework.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.