So it's particularly gratifying to see that the chaps behind it are launching a geodata-related business, called Mappam:
Mappam helps you make money by adding relevant ads targeted to the exact place your visitors are browsing.
It's easy to set up and works with all the big web map services - Google, Yahoo!, Microsoft, MultiMap and OpenStreetMap/OpenLayers.
Let's hope they've, er, found a way to make lots of dosh. (Via OpenBusiness.)