I moderated a Radio Show on 3D printing the other day, and it gave me a pretty good education on the basics of this technology.
It's funny how many misconceptions there are about 3D printing and additive manufacturing. The first misconception is the difference between 3D printing and additive manufacturing. While there are some subtle differences, most people use them interchangeably, and that's OK.
The second misconception is the cost of the technology. While you still aren't likely to have one of these printers located in your family den, the technology is definitely available to small and midsized businesses.
The third misconception is in the quality of the output. There are numerous examples where the output of the 3D printer ends up being the final product. Most people think that these systems are just for prototypes, but depending on the application, that may end up being your final part, especially if your run is very small.
Bottom line -- I learned a lot about this technology that's clearly here for the long haul.