cdnjs is a free distributed JS library delivery service.
DoubleClick Ad Exchange is a real-time marketplace to buy and sell display advertising space.
Google AdSense is a program run by Google through which website publishers serve advertisements that are targeted to the site content and audience.
MediaWiki is a free and open-source wiki engine.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Varnish is a reverse caching proxy.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.