AddThis is a social bookmarking service that can be integrated into a website with the use of a web widget.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Twenty Eleven is the default WordPress theme for 2011.
Twitter is a 'microblogging' system that allows you to send and receive short posts called tweets.
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.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.