Many years ago I had an idea for "emergency help with computers" but didn't do anything with it. A couple years later all of Moscow metro was suddenly covered w

Many years ago I had an idea for "emergency help with computers" but didn't do anything with it. A couple years later all of Moscow metro was suddenly covered with leaflets advertising "emergency help with computers". Once I had an idea about adding georeferencing data to regular photos of landscapes - not just top-down images - to overlay them on the 3D terrain. Later this capability appeared in Google Earth for user photos and it looks great.