Apache is a free and open-source cross-platform web server software.
Disqus is a worldwide blog comment hosting service for web sites and online communities that use a networked platform.
Endurance Page Cache adds basic file-based caching to WordPress.
Google Analytics is a free web analytics service that tracks and reports website traffic.
vBulletin is tool that is used to create and manage online forums or discussion boards. It is written in PHP and uses a MySQL database server.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.