Google Tag Manager is a tag management system (TMS) that allows you to quickly and easily update measurement codes and related code fragments collectively known as tags on your website or mobile app.
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.
Lightbox is small javascript library used to overlay images on top of the current page.
Modernizr is a JavaScript library that detects the features available in a user's browser.
PayPal is an online payments system that supports online money transfers and serves as an electronic alternative to traditional paper methods like checks and money orders.
PHP is a general-purpose scripting language used for web development.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.