As a non-js based programmer, This is some excellent insight in what a webapp looks like when built with node.js. I'm definitely gonna be reading through this to get my feet wet with node, as it's something I've been meaning to do but have been so occupied with other languages. Thanks for sharing!
If you are new to Javascript you should note that this tutorial makes heavy use of Promises which is one way to handle callbacks piling up, but it's not the only way, or even the most common.