Beet, since you seem to know something about it, could you explain 3D Printing in a way that isn't just "miracle device out of Star Trek that can fabricate objects out of sawdust?"
There are numerous different advanced manufacturing techniques all being grouped under the category "3D Printing", the common element being that they are all what is now called "additive manufacturing techniques." Traditionally manufacturing is subtractive, meaning that parts are created the way a sculpture is, by taking a chunk of the base material and then cutting away parts of it in a process known as machining. Additive manufacturing techniques use only the amount of base material that will actually be in the final product, building it up piece by piece. The advantage of additive manufacturing is that it is much quicker to change the design, which is why it has been used for decades for rapid prototyping. The disadvantage now and ever is that it's not efficient for producing large quantities (>a few thousand).
What's happening now is that the quality of rapid prototyping is improving and the cost is coming down to where it's starting to approach the consumer level (but not yet). I would say consumer 3D Printing is where the PC industry was in the mid-1970s. The cost-benefit is low enough for enthusiasts and hobbyists to adopt, but not worthwhile (yet) for the general public.
The main limitation of the current consumer models, IMO, is the limited material they can use (only plastic). Essentially it's a chemistry limitation. Current consumer models all use a variant of fused deposition modelling, which is where the raw material (filament) is fed into a nozzle by a motor. The nozzle is heated to melt the filament as a very thin layer of it (usually between .01 and .1 mm) extrudes out from the nozzle, and settles onto the surface of the base. At the same time stepper motors are used to move the nozzle around rapidly, creating a "layer" of object. Then, the base is lowered by .01 to .1 mm and the process is repeated again, creating the next layer. The material is typically a plastic and comes out as the same plastic that are used in Lego sets. But since only plastic can be used (due to it's melting point properties, can't be too high) you can't use these devices to print circuit boards, glass, rubber, wood, etc. So obviously their utility is very limited. Further, they're usually monochromatic or bichromatic. The current models run at about $1300-$1700. Until some of these big limitations are overcome and the cost comes down under $500, you won't see this become a household item. But given the progress that has been made in the past several years, I wouldn't be surprised if these problems were indeed overcome. Other types of 3D Printing, such as laser sintering, can definitely print metals.
As has been the trend for decades, manufacturing will require more skilled jobs (some of the more delicate stuff may still be by hand, but there will be more engineers and fewer poor immigrants on assembly lines). While unskilled labor has been dead for a while, manufacturing may actually increase as a sector.
Actually, the advent of 3D printing may actually increase the proportion of unskilled labor in manufacturing, by allowing anyone or even little children to manufacture things at the click of a button.
Technology certainly isn't increasing the number of jobs in the US. More profits does not equal more jobs. Verizon is sitting on $10 billion, and they laid off 40,000 people in the last few years.
Indeed, technology advances usually mean more efficiency and fewer jobs. Still better than the alternative.
That really isn't true; I mean, are there more jobs now, or were there in 1800?
In theory, technology is supposed to lower costs, which increases demand. As demand increases, then jobs are created to fill that demand.
What's happening now is a bit more complex. It's a part of the overall increased stratification of the world between haves and have-nots. Only in this case the "haves" are the select few with the engineering, computer, energy and medical skills that are in demand, while the "have nots" are everyone else.