If you don't know what knockoutjs is, I highly suggest you take a look at it. It's a pure javascript library that can be used to build UI based on the MVVM pattern. At the time I started developing modeljs I did not know about knockoutjs. The main web MVC framework I was evaluating was backbonejs. I liked a lot of the concepts in backbone, but didn't quite like framework, which gave me the motivation to create modeljs.
When I started modeljs I decided to limit my scope to designing just the model aspect of the MVC framework. I wanted modeljs to be able to be used in any landscape possible and I didn't want it to dictate how you should build controls or how your should design your application. I think I've succeed in this. Modeljs is node compatible, which means it can be used server side code and potentially in other application that I haven't imagined yet.
At the time I was almost ready to release version 1 of modeljs I learned about knockoutjs and was immediately impressed. It was easy and was more what I expected a good javascript MVC UI library. I immediately looked at examples and was interested if modeljs could provide the same functionality. Up to this point, I've always had the concept of creating a binding library on top of modeljs, but seeing knockoutjs was both exciting and upsetting. Exciting because it clarified some of thoughts I was having about the binding library I was intending to create and upsetting because it was already done and creating a copy didn't seem useful.
With all that said here is how a quick knockoutjs binding library can be created on top of modeljs. That page similates the knockoutjs introduction tutorial.