MVC, more than other design patterns, is horribly abused. Developers should keep in mind its GUI roots. Here's my "is it MVC?" litmus test:

How much of my code survives if I drastically change the view?

For example, if I want to switch to a new desktop, web or text console interface, can I reuse much of the application? Of course, architecture changes this significantly (particularly web architecture), but still, if I cannot swap out the view, then I'm losing out on one of the significant advantages of an MVC architecture. One way to make sure this works is to start with 2 views from the beginning - the view you're actually going to ship, and a headless view for tests.

my rails apps pass this test with flying colors. Nearly all of my end points have at least 3 views. 1 for html, 1 for json (often used for ajax calls), and 1 for rss/atom.

JSON and RSS views don't make sense - in MVC, views are visual representations of data (the model). Views are how the user percieves the application. JSON and RSS are just different methods for representing data to be communicated to other systems.

HTML is also one of those different methods. It just so happens that the browser renders it instead of spitting out the raw text.

That said, non-HTML output bypasses the view entirely in Rails (it makes sense to), so it can equally be the case that the distinction is correct.

https://github.com/rails/jbuilder/

It looks a lot like a view file :)