For me -
Fly fishing is where during the cast the power generated by moving the rod is transferred to the line which provides the energy to deliver my lure (fly) to the intended target. In other words the fly is along for the ride.

For gear fishing during the cast the power generated by moving the rod is transferred to the lure. In other words the line is along for the ride.

Clearly much of what has been dicussed (small spoons, bobber and jig flies, etc) is a hybrid between the two. Thus to my definitions throwing small spoons with the bug rod or strip casting un-weight eggs with the gear rod is more "fly fishing like" than throwing bobber and jigs with the fly rod or drift fishing with sinker and fly which are more "gear fishing like".

My philosophy is that all forms fishing are enjoyable and if your choice of method is within the regulations have a good time; just respect your fellow anglers.

Tight lines
Smalma