Then again, maybe it doesn't much matter. A thick slab of lightly toasted good quality bread topped with delicious ingredients is an almost unbeatable comfort food no matter what you call it. Maybe it's because it reminds us of when we were kids and Mom would make toast for breakfast or to have in bed when we were sick. Or maybe it reminds us of late night snacks in college.
We're not entirely sure what the difference is between a classic open-faced sandwich and the suddenly hip world of toast with toppings.