AddThis is a social bookmarking service that can be integrated into a website with the use of a web widget.
Google Hosted Libraries is a stable, reliable, high-speed, globally available content distribution network for the most popular, open-source JavaScript libraries.
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.
OWL Carousel is an enabled jQuery plugin that lets you create responsive carousel sliders.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.