When clicking the 'Location' field on the careers site, I can choose a distance… in miles…
Most people on this planet don't really know what a mile is and if they are like me, they don't really care :-/
So I suggest you add the option to use the metric system, or if the option already exists, to make it (much) more visible, because I couldn't locate it.
Just to let you know that this could be a big deal, let me show you a map of countries using the metric system (Hint: it isn't the red ones O.o):
Anyhow, I know Liberia, Burma and such are important markets for Stack Exchange, but the rest of the world uses this site as well ;-)