Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
PHP is a general-purpose scripting language used for web development.
Twenty Eleven is the default WordPress theme for 2011.
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.
WordPress is a free and open-source content management system written in PHP and paired with a MySQL or MariaDB database. Features include a plugin architecture and a template system.
WPMU DEV Smush is a WordPress plugin that allows you to optimise images without losing quality.