Source: http://nodejs.org/Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.
Links:
https://github.com/joyent/node
http://radar.oreilly.com/2011/07/what-is-node.html
http://www.sitepoint.com/node-js-is-the-new-black/
http://www.sitepoint.com/whats-node-js-all-about/
http://nodeguide.com/
http://nodemanual.org/latest/
Litterature:
http://www.nodebeginner.org/
http://www.sitepoint.com/books/nodejs1/