Based on data bought from the Danish Statistics Office you can search on a family name and see it's absolute and relative occurance in different Danish municipalities.

Over 73.000 different family names can be searched on.

Made by Tommy Kaas and Nils Mulvad.
See the mash-up working at http://xpoint.experian.dk/navnekort/

Related mash-up: Navnelaboratoriet by Finn Jordal