Obvious/matador — pull request #78 by breerly (2012-07-02 21:14:43+00:00)
Title: Adding PORT environmental variable support.

Useful for deployment and on PaaS services like Heroku.

For example, Heroku uses a different port for each deploy. Luckily, the port number is stored in an environmental variable called PORT.

https://devcenter.heroku.com/articles/nodejs