Ever wonder how many people may have your surname or a certain surname? Ever want to find out where those people live? There's a need web-based application that I've discovered called publicprofiler/worldnames.
Basically go to the Name Search tab, enter a surname in the Surname field and click Search.
A world map appears listing where the concentration of that name is low to high. Looks like I have some MacEntees to track down in Alaska of all places!
You can also zoom in to specific countries, in my case Ireland:
And at the bottom of the page is a statistical breakdown of the surname:
I guess this could be a valuable tool but it wasn't clear the origination of the data. The FAQ for the site states they have "data for approximately 300 million people in 26 countries of the world, representing a total population of 1 billion people in those countries. In our database there are 8 million unique surnames and 5 million unique forenames" all from "world records."