Not if you're unfamiliar with Ruby on Rails, I guess. It's a little tricky to characterize because of how much stuff it contains. Basically it has a number of different components, that work together to make a structured environment for developing Web applications. Some of the prominent features include:

* Web server that runs on Node.js

* MongoDB integration

* Custom build tools

* Package manager (supports installing JS packages for either client-side code, server-side code, or both).

* SignalR-style remote function execution (call functions on the server from the client, and vice versa)

* JS client-side database caching

* Data binding in Javascript templates using Handlebars (or something similar, I don't remember exactly).

etc.

I thought it was answered pretty succinctly.