AddThis is a social bookmarking service that can be integrated into a website with the use of a web widget.
Bluehost is a large web host known for its WordPress expertise, variety of “one-stop-shop” services, and bargain prices.
Endurance Page Cache adds basic file-based caching to WordPress.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Optimizely is an experimentation platform that helps developers build and run A/B tests on websites.