Ruby is a dynamic, reflective, general-purpose object-oriented programming language that combines syntax inspired by Perl with Smalltalk-like features. It was also influenced by Eiffel and Lisp. Ruby was first designed and developed in the mid-1990s by Yukihiro "Matz" Matsumoto in Japan. wikipedia.org

Cascading Style Sheets (CSS) is a style sheet language used to describe the presentation (that is, the look and formatting) of a document written in a markup language. wikipedia.org

AngularJS is an open-source web application framework, maintained by Google and community, that assists with creating single-page applications, one-page web applications that only require HTML, CSS, and JavaScript on the client side. wikipedia.org

JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles. wikipedia.org

Ruby on Rails, often shortened to Rails or RoR, is an open source full-stack web application framework for the Ruby programming language. wikipedia.org

HyperText Markup Language (HTML) is the main markup language for web pages. HTML elements are the basic building-blocks of webpages. wikipedia.org

The Twitter API allows other web services and applications to integrate with Twitter. It currently supports website embedding, a REST API, a streaming API, a framework for the iOS, and the OAuth authentication protocol.

Heroku is a cloud platform as a service (PaaS) run by the San Francisco, California-based company with the same name. Heroku led the way for a multi-language PaaS, introducing the 'polyglot platform'. Heroku PaaS now supports six languages: Ruby, Java, Node.js, Scala, Clojure and Python cloud PaaS. wikipedia.org

The Facebook Platform provides a set of APIs and tools which enable third-party developers to integrate with the "open graph" whether through applications on Facebook.com or external websites and devices. wikipedia.org

Email marketing is directly marketing a commercial message to a group of people using electronic mail email. wikipedia.org