Node.js showed up at the right time. PHP, currently the most popular server-side language, has been mired in community squabbling amidst a large effort to refactor its character encoding support, while also losing developer mindshare to the many excellent Ruby web frameworks that have appeared in the last few years. But Ruby web frameworks, and the language itself, have become notorious for having performance issues and sometimes being hard to scale (although some of this perception is based on misinformation), so the appearance of a new highly performant, highly scalable evented IO framework built on top of the world’s most popular programming language couldn’t have been better timed.
Ruby is a great language, you can do functional programming with it, you can do asynchronous/evented, and you can do objects right. But it doesn’t come easy, and not all the libraries you use will play along. Quite a lot of libraries are mixed style.
Contrast with JavaScript: it’s functional, evented and has the prototype object model. It was designed that way, and encourages people to develop to that style, which helps you when everything up/down the stack works the same way.
Few quotes from Quora about Node.js
Ryan Grove, YUI engineer at Yahoo!
Assaf Arkin, http://labnotes.org