Ask HN: Examples of applications built with Node.js?

It's hard to find any examples of applications built with Node.js. Do you have any examples on applications that are fully or partly built with Node.js?

A very cool one: real time website analytics:

http://demo.hummingbirdstats.com/

http://rdelsalle.blogspot.com/2010/05/real-time-web-analytic...

Here's a little Node.js/CoffeeScript application I worked on for a contest at a conference:

Site: http://apiplayground.org

Source: http://github.com/jashkenas/api-playground/blob/master/src/a...

The source is interesting because it demonstrates something that you can't do easily with a regular Rails/Django app: nonblocking asynchronous calls to remote APIs, with synchronous responses to the ajax request.

In fact, what would be a use case of Node.js?

I know it is a rather interesting tech but other than that what do you/would you use Node.js for?

Here's an offline-capable web application and underlying "network-straddling" framework running on Node:

https://szpil.com

Node is great for handling many concurrent clients. It extends the V8 interpreter with excellent low-level APIs: Posix, Tcp, Http, DNS. If you need to share Javascript code between client and server, Node is the best server-side Javascript environment you could choose to use.