I'm new here, and I'm curious as to how this website works. I know kraftwurx is a 3D printing company, but how does the system work?

You can find a lot of information on how the system works Here

Short version: Kraftwurx serves as a company that brings together 3D printing Bureaus all over the world who will 3D print YOUR products out of various materials found here. Along with bringing together these bureaus, kraftwurx serves as an online store, allowing virtually anyone to upload their 3D models to be printed.

So, Kraftwurx serves as a company that allows anyone to open a store featuring their 3D models.