Apache is a free and open-source cross-platform web server software.
cdnjs is a free distributed JS library delivery service.
DoubleClick for Publishers (DFP) is a hosted ad serving platform that streamlines your ad management.
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.
Twitter is a 'microblogging' system that allows you to send and receive short posts called tweets.