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.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
YUI is a JavaScript and CSS library with more than 30 unique components including low-level DOM utilities and high-level user-interface widgets.