Briefly, in much of the world, babies don't use diapers and certainly not the extent and duration we do in the US. The link describes the methods and rationale for diaperless babies. Like breast feeding, diaperless babies are the norm throughout history and still throughout the bulk of the world, but both have left the mainstream in the "developed" world. It seems odd to me that decreasing the bond and communication between parent and child, increasing cost, and generating mountains of garbage are considered progress. I wish I'd seen this when the kids were still in diapers (although I doubt Michelle would have gone for it...)
As a funny aside, the article talks about the shii shii sound that parents use to signal kids to pee; I totally grew up with my parents making that sound to help us get started, and I do the same with the boys. I never knew why we did this.