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.
Priority Hints exposes a mechanism for developers to signal a relative priority for browsers to consider when fetching resources.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.
UIKit is the framework used for developing iOS applications.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.