nano

First, Check out this link.

"The third generation [of nanotechnology] is expected to begin emerging around 2010 and will feature nanosystems with thousands of interacting components. A few years after that, the first integrated nanosystems, functioning (according to Roco) much like a mammalian cell with hierarchical systems within systems, are expected to be developed."

"A computer can make copies of data files—essentially as many copies as you want at little or no cost. It may be only a matter of time until the building of products becomes as cheap as the copying of files."

I was having a hard time visualizing how these machines would work until I saw this animation:

(each of those dots is one atom. the way in which the atoms interact and bond creates a machine, in this case a stepper gear the size of a large molecule. by linking nanomechanical devices together with nanocomputers you could create a robot the size of a bacterial cell which could perform any number of functions)

So basically, the physical world will take on many of the attributes of the internet. Physical structures will be able to be 'programmed' at the molecular level. Portable nanofactories will be a household applicance. No, scratch that... portable nanofactories will be THE household appliance. You can download a nano blueprint and the machine will construct whatever physical device that blueprint describes. They estimate that the Library of Congress will be able to be stored on a computer the size of a sugar cube, or that they could construct materials thousands of times stronger than steel at one hundredth the weight. Nanomachines could be introduced into your body to target and destroy cancer cells (or any disease vector really). We could potentially upgrade our own bodies in ways we can't even imagine.

Either this is the next big evolutionary stage in human existance or it's the apocalypse.