I recently created this JSON generator for Modelo, the online 3d publishing and collaboration platform that I founded. link: modelo.io

You could watch this video here to learn how to upload your model directly from Rhino/Grasshopper to Modelo and share it with others.

Modelo Upload Tutorial from Modelo.io on Vimeo.

Here is the link to the example and plugin files. 

https://dl.dropboxusercontent.com/u/7749202/Modelo%20Exporter%20Plugin%20and%20Example.rar

and here is how it looks to be embedded in other pages.

www.nonearchitecture.com