So, yes. Non-blocking I/O is a standard library feature, but it works because of language features.
Event loops are not a property of JavaScript of any other programming language: Every single GUI Win32 application ever written in C directly calling the WinAPI contains an explicit event loop.
> "(...) in a way that no other popular language does. Because of this, javascript has features that make this type of programming easy - first-class functions, anonymous functions, etc."
JavaScript is hardly the only language, or even the only popular language, to ever have first-class procedures or anonymous procedures. You know what (at some point in time) widely taught language has a procedure data type[1]? Pascal. So why not Node.pas instead?
> "So, yes. Non-blocking I/O is a standard library feature, but it works because of language features."
That countless other languages have. Most of them a lot better designer than JavaScript.
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[1] Edit: I originally suggested Pascal has anonymous procedures, which it does not.
C# Async and Await - http://msdn.microsoft.com/en-us/library/vstudio/hh191443.asp...
In .Net 4.5 there are Async versions of the web, file, stream, image and SQL category of functions.
It's also making its way into ASP.Net layer.