This is a tough question to answer. I think it's very possible that the initial wave of 3D Printing will take place in stores. Most people likely don't want to spend a couple thousand bucks for a really useful printer, nor do they have the patience to learn how to use them, etc. I think in the next 5 years we will see thousands of stores adopt 3D Printing like Home Depot, Walmart, etc. There will even be entire storefronts which are set up only to 3D Print people products on high quality machines. I then expect that by 2018 or 2019 consumer printers will be cheap enough, have cheap enough filament, and be extremely high quality where mass adoption will begin taking place.