Is Microsoft's MVC implementation different from classic MVC pattern

In various articles on the web about ASP.NET MVC I've people mention that Microsoft's implementation of MVC is somehow different form the 'classic' MVC pattern.

But I've never seen anyone go into any detail on this, and at first glance I don't see how ASP.NET MVC is any different from what is described, say, here.

So my question is: does ASP.NET MVC really violate any MVC pattern principles?