I also see them referred to as Rhumb lines...but I dont' think thats correct, because a rhumb line is a line of constant bearing on a sphere (loxodrome)...kind of spirals around a map or something...but if the lines are drawn using rhumb line formulas (cosines and crap) then that makes sense.

I think its something worth looking into, because there may be a useful science we've all been overlooking here that could improve all our maps.