Google Analytics is a free web analytics service that tracks and reports website traffic.
Google Publisher Tag (GPT) is an ad tagging library for Google Ad Manager which is used to dynamically build ad requests.
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.
Modernizr is a JavaScript library that detects the features available in a user's browser.
RequireJS is a JavaScript library and file loader which manages the dependencies between JavaScript files and in modular programming.
Twitter is a 'microblogging' system that allows you to send and receive short posts called tweets.