In any case, the real issue at stake is whether there is anything about Node.js that makes it particularly good for writing server-side applications. As far as I can tell, the only thing Node.js brings to the table is an event loop. Event loops are not a particularly earth-shattering concept: Anyone who has written a graphical Win32 application by directly using the WinAPI has written an event loop (message loop in Win32 parlance). I do appreciate not having to write the loop myself, but:

1. An event loop can only handle concurrent I/O. Furthermore, because the event loop is hardcoded into every single Node.js instance, there are two legitimate choices that are nevertheless unavailable to a Node.js programmer: a) disabling the loop, if he does not need it, b) spawning multiple event loops as separate threads within a single Node.js instance.

2. Node.js offers no support whatsoever for concurrent computation. I know, I know, all your Web application does is move data between a database and a client. But, if the only use case of Node.js is going to be making Web applications, would it not have been better to make a Web application framework, and provide it as a library?

Languages that actually provide concurrency support (Erlang, Haskell and Rust, to name a few) make writing event loops as easy as it used to be in the 1990s. On top of that, they can be used to write server-side applications that scale.