from "The cat with more than 500,000 Twitter followers"
1.Internet Relay Chat
Internet Relay Chat (IRC) is a form of real-time Internet text messaging (chat) or synchronous conferencing. It is mainly designed for group communication in discussion forums, called channels, but also allows one-to-one communication via private message as well as chat and data transfers via Direct Client-to-Client.
2.Ruby on Rails
Ruby on Rails, often shortened to Rails or RoR, is an open source web application framework for the Ruby programming language. It is intended to be used with an Agile development methodology which is used by web developers for rapid development.
Starling is a light-weight persistent queue server that speaks the memcached protocol. It was originally developed for Twitter's backend.
4.Scala (programming language)
Scala (pronounced /ˈskala/) is a multi-paradigm programming language designed to integrate features of object-oriented programming and functional programming.
Self-referentially short for PHP: Hypertext Preprocessor, an open source, server-side, HTML embedded scripting language used to create dynamic Web pages.