Pythonistas could think of Node.js as the JavaScript equivalent of CPython, Twisted, and setuptools packaged together in a single binary residing server-side. It includes a package repository (npm), and is all about event-driven I/O. That means that every time you make a call that would block, you pass a callback to it, kind of like how Twisted’s Deferreds work.—Pete Hunt...

Node.js performance tips from LinkedIn