Think of it as a Mini Countryman that happens to look like a Fiat 500. The "L" in Fiat 500L apparently stands for "Large, meant as functionality and space; Light, when 'lightness' means user-friendly technology and eco-friendliness; and Loft, a trend-setting environment where one can live life to the fullest."
While the last two of those of the three might be a bit of a linguistic stretch, the first two sure seem to fit the bill. The cleverest feature of the new Fiat is probably the sliding rear bench seat. Rather than having it bolted in place, the bench is on rails, so that it can move forwards or backwards depending on one's need for either extra cargo space or extra leg room.
No word on when it will be available stateside though.