cdnjs is a free distributed JS library delivery service.
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.
Linkedin Sign-In is an authentication system that reduces the burden of login for users, by enabling them to sign in with their Linkedin account.
Open Graph is a protocol that is used to integrate any web page into the social graph.
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.
RevolverMaps is a collection of real-time visitor statistics widgets for website or blog. Interactive visitor mappings to a globe rendered by the Revolver Engine.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.