Some sites allow for readers of a document to make annotations in the margin. qz.com and medium.com are examples of this. I would like to easily allow for readers to easily contribute to my documents. It is possible to enable "comments" on otherwise static web content using javascript and services like disqus.com but as far as I'm aware there is not a drop in solution like that for enabling commentary (or notes) on each paragraph in a document. So now I wonder, how can I make this happen. Please respond below or e-mail me if you know how to do this.

Update May 6th 2015: Thanks to http://carnivalapp.io/ coming into existence, this problem is now solved.