Ask HN: What are your thoughts/experiences with right click menus in web apps

I am programming an ASP.NET web application at the moment and part of the functionality is to allow file uploads. It will have drag and drop functionality as one method of uploading and the traditional open file dialog button as another but I am torn on using right-click instead of or in addition to one of the other methods.

Now, we will all be familiar with right-click in a native application at least, however, this isn't something I routinely use in a web application, except on outlook.com (which I think does it quite well). On a tablet, it would be a long click to simulate right click.

I would love to know the thoughts of others that have done it and how the users took to it (if they were even aware of its existence). Also, any examples of it done right (and wrong too!) would be appreciated.