Apache is a free and open-source cross-platform web server software.
Imgix is a visual media platform for managing, processing, rendering, optimising and delivering your existing images.
Open Graph is a protocol that is used to integrate any web page into the social graph.
PHP is a general-purpose scripting language used for web development.
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.