Google AdSense is a program run by Google through which website publishers serve advertisements that are targeted to the site content and audience.
Gravatar is a service for providing globally unique avatars.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
NitroPack creates optimised HTML cache for fast page loading experience.
Open Graph is a protocol that is used to integrate any web page into the social graph.
SiteGround is a web hosting service.