cdnjs is a free distributed JS library delivery service.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Phusion Passenger is a free web server and application server with support for Ruby, Python and Node.js.
Ruby on Rails is a server-side web application framework written in Ruby under the MIT License.
Twitter is a 'microblogging' system that allows you to send and receive short posts called tweets.