I'd forgotten about this until I saw the post about a family surname in Potenza - apologies if it's been posted before but I think it's really interesting -
Just put an Italian surname into the box on the top right and the map will show you where it's found. It's amazing how 'local' most surnames still are in Italy - I can't imagine a UK version of a map like this would really show anything of interest. Obviously the really common ones like "Rossi" are pretty much everywhere, but some are very specific to certain areas. I tried all my Italian friends' surnames and they're mostly found just around the area they're from.
Just thought it might be vaguely of interest to someone!