Apache is a free and open-source cross-platform web server software.
Ubuntu is a free and open-source operating system on Linux for the enterprise server, desktop, cloud, and IoT.
W3 Total Cache (W3TC) improves the SEO and increases website performance and reducing load times by leveraging features like content delivery network (CDN) integration and the latest best practices.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.