Apache is a free and open-source cross-platform web server software.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Popper is a positioning engine, its purpose is to calculate the position of an element to make it possible to position it near a given reference element.
TYPO3 is a free and open-source Web content management system written in PHP.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.