This is a post by Helga Stroehle on PTC site.
Prior to the Industrial Revolution, products were created by craftsmen, usually by hand, and always on a one-by-one basis. Making anything of quality was a laborious process, limiting their availability to the few who could afford it. Mass production changed all that, and in the process created our modern world.
That revolution in product design worked by giving everyone more or less the same thing, and by making that same thing relatively inexpensive to produce. However, with current and coming advances in 3D printing, CAD software and consumer communications, the core idea of the Industrial Revolution – minimizing variation – is giving way to something new: mass customization.