To make a permanent magnet, you can't just magnetize a chunk of iron. It doesn't take. Up until this discovery, magnets were made primarily of tungsten, steel or an alloy of aluminum, copper and nickel. Then, the General Electric Company had the brilliant idea to use iron dust and embed the tiny particles in glass, plastic, rubber or another metal.
The magnets that resulted were much stronger, and could be fashioned into fun shapes, like Christmas trees, instead of the boring old horseshoe that everyone was pretty much sick of by that point.
Read the full story in Iron Dust Makes Supermagnets