Wikipedia
HipChat is a Web service for internal/private chat and instant messaging. As well as one-on-one and group/topic chat, it also features cloud-based file storage, video calling, searchable message history and inline image viewing. HipChat is available to download onto computers running Windows, Mac or Linux, as well as Android and iOS smartphones and tablets. HipChat is currently based on a freemium model, as much of the service is free with some additional features requiring organizations to pay $2 per user per month.
Having launched in January 2010, HipChat was founded by Chris Rivers, Garret Heaton and Pete Curley, the trio behind HipCal and Plaxo Pulse. HipChat was later acquired by Atlassian in March 2012.
HipChat has surpassed the billion message mark and has entered a cycle of exponential growth, as the number of messages has doubled every few months. As of January 2014, it was estimated that the service handles 60 messages per second and boasts 1.2 billion messages stored and half a terabyte of searchable data. HipChat is mainly written in PHP and Python using the Twisted framework, but features an extensive platform that utilizes numerous third-party services.