AddThis is a social bookmarking service that can be integrated into a website with the use of a web widget.
Lightbox is small javascript library used to overlay images on top of the current page.
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.
PHP is a general-purpose scripting language used for web development.
Prototype is a JavaScript Framework that aims to ease development of web applications.