Application Request Routing (ARR) is an extension to Internet Information Server (IIS), which enables an IIS server to function as a load balancer.
Azure is a cloud computing service for building, testing, deploying, and managing applications and services through Microsoft-managed data centers.
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.