There's one key difference between Node.js and Twisted / EventMachine / other non-blocking IO frameworks for existing languages: Node.js doesn't have any blocking function calls. You have to try really, really hard to block your event loop in Node.js. Every single library released for Node.js works asynchronously, and is hence safe to use.<p>Not having to even worry about whether or not a library I want to use is blocking is a really useful feature.