This is a twelve year old question you are answering, but I am quite glad you did.
That video presents by far the best explanation I've seen or heard.
I studied italian for a few years in the early nineties and have been to Italy a few times, on very satisfying trips. That video makes me want to refresh my memory of the language I somewhat understood back then. The last time I was there, 1999, I could still make my way alone through different cities with my mediocre italian. People there tend to support those who are trying to learn.