Note: Nanotechnology is a “slippery slope” technology. While players are encouraged to be innovative and create interesting characters, consultation with Roleplay Staff is required prior to inclusion of technologies such as those listed below in a character's cinfo or tinyplot idea. - Hagalaz
Although nanomachines are tiny, many of the things built with them are large – even gigantic. During the heyday of nanotechnology (sometimes referred to as the 'Diamond Age', in a manner similar to prior archeological ages such as Stone, Bronze, Iron, etc..) it was used to manufacture all kinds of materials and items with atomic perfection. For example: a rocket engine made from synthetic sapphire, or bi-phase carbide armor for military vehicles, or the lift cable for a space elevator. Practically anything made with nanotech would be more efficient and more effective than its present-day counterparts.
Nanomachines are non-living, and are incapable of being mutated. Malicious nanomachines could destroy other nanotech, and use the raw materials in an assembler to create more malicious nanomachines, but it would take a functional assembler, backed by a functional supercomputer or AI, to modify existing designs to create new nanomachines.
NANOTECH MATRIX: Also called utility fog, it's a mass of micrometer-scale nanomachines that can rearrange themselves into different shapes. Before the Apocalypse War, artificially intelligent creatures were created uses this technology, and the most advanced ones could shape-change in a way similar to the T-1000 from the movie Terminator 2. (Some were used as “living cartoons” on television or at amusement parks!) These things have some limitations, though…. They are not physically strong. They don't eat ordinary food, instead they have to recharge or refuel from time to time with electricity or hydrogen gas, depending on the design. And they are not self-replicating or self-repairing. As time goes by (i.e. years and decades), individual nanomachines (or foglets) from the mass get lost or break down, and they can't replace themselves, so the mass of the creature is reduced. These creatures were uncommon before the war, and should be very rare today (nanotech utility fog hasn't been manufactured for over 150 years!). The technology to create new utility fog isn't available, it was never re-developed after the war.
VIRTUAL REALITY: Instead of creating a creature from utility fog, it's possible to fill a room with the stuff and have an immersive environment similar to the “holo-deck” of Star Trek fame. Nothing in the fog chamber is real, it's all illusion created by the fog. Maintaining a fog chamber runs into the same problems of lost or broken foglets, so it's doubtful whether any are still operating today. If a small one were still working, it would be highly valuable for research. If a larger one were operating, it could become a very successful public attraction. Other forms of virtual reality are available in our setting, like the suit-and-goggles rig or CAVE displays, but they aren't nearly as effective as the “lost” technology of nanofog chambers. A nanofog chamber is the only VR technology good enough to fool someone – at least part of the time – into thinking what he sees and feels is real.
BUSH ROBOTS: While not the nanomachines commonly imagined when nanotechnology is mentioned, they were capable of manipulating nanoscale objects. Picture a robotic arm that has limbs that branch, fractally, in clusters of three, so that each branch supports three branches, that in turn support three smaller branches, that in turn support three smaller branches… all the way down to a nanometer scale. Such 'bush robots' or 'bushbots' were capable of manipulating objects on a near-atomic scale, with trillions of fingers - each one essentially tipped with an atomic force microscope. Controlling the positioning and function of every single one of these 'fingers' would have required extensive computer processing, probably involving a dedicated AI. Bush robots would have been capable of performing a number of feats at nanoscale, for example: reading and editing chromosomal information, or performing surgical procedures at the cellular level. The ability to manufacture these robots was lost during the Apocalypse War.
MILITARY NANOMACHINES: During the 'Diamond Age' of humanity, micro-sized robots were created that could serve a number of specialized functions on the battlefield, such as reconnaissance, attack/defense, equipment repair, and providing field emergency medical care. These tiny robots functioned best in large groups (a typical swarm would hold around one thousand individual robots), and, as a swarm, were capable of semi-autonomous operation to accomplish specific tasks (each type of microbot swarm was equipped with specialized, task-specific tools and sensors). In the years immediately prior to the Apocalypse War, technological advancements allowed for further miniaturization of these microbots into nanoscale machines capable of the same functions. The ability to reproduce combat nanobots - and their larger microbot cousins - was lost as a result of the Apocalypse War, but horror stories of combatants being reduced to 'ground meat' - and of rogue clouds of hungry nanobots prowling Earth - persist to this day.
VACUUM DIAMONDOID CIRCUITRY: In the early 21st Century, Vanderbilt University, using a grant from the United States Army, pioneered research into creating nanoscale logic gates and transistor-like circuits out of nanoscale diamondoid film. Applications included military electronics, circuitry that operates in space, ultra-high speed switches, ultra-low power applications and sensors that operate in high radiation environments, at extremely high temperatures up to 900 degrees Fahrenheit and extremely low temperatures down to minus 300 degrees Fahrenheit. Additionally, EMP resistance was found to be similar to old-fashioned vacuum tubes. Because the electrons in vacuum diamondoid circuits flow through empty space, instead of bumping into atoms in a silicon chip's pathways, heat management is a non-issue. (OOC Note: See here for a news item regarding lab research into this field. Also, while the circuits themselves may be EMP-resistant, things attached to said circuits, such as motors, artificial myomer, sensors, etc… are NOT. - Hagalaz)
One of the few areas where new nanomachines are still manufactured and used is in the medical field. These are injected or ingested into the body, and are pre-programmed to perform some useful function: scrubbing artery walls, scavenging for toxic molecules, killing viruses, bacteria or cancer cells, inserting gene therapy, compensating for mutational stresses, or repairing some forms of tissue damage. They can be highly effective and are a powerful tool in the medical trade, but they don't perform miracles of healing massive wounds overnight or giving the patient super-powers. Neither do they stay for very long in the body. In a matter of days, or more often hours, they will run out of fuel, break down, and be cleaned out of the body, usually through the kidneys.
NANOSITE IMPLANTS: Nanotechnology would have been used to produce medical implants before the war, and these would be better in most respects than anything available 'today' in the early 23rd century. Of course, to have one of those implants, you would have to explain where it came from – considering it's been roughly 150 years since any were made.
ANTI-AGING: In the last years before the Apocalypse War, a complex life extension treatment called UAG-7 was developed that could permanently halt the aging process in humans (this is why Dr. Somtow is still alive, for one example). It was never widely available to the common people, and its secret was lost in the war. Thus, anybody wanting to play a non-aging survivor from Earth will need a special dispensation from the RPstaff. Most furry recoms are naturally long-lived (Zobeid observed once that “Furries age in 'Lucy Liu years'”, because she was 34 years old but looked 19.) Treatments are available to help recoms age gracefully and extend their lives even further, but the medical technology to halt aging completely is no longer known.
INFECTIOUS NANOMACHINES: Nanomachines cannot live and reproduce inside someone's body (with a very few specialized exceptions, such as UAG-7), and they can't spread like a virus from one person to another. Any kind of infections we have are limited to bacteria and virii, and they can only do the sorts of things that are at least semi-plausible for a bacterial or viral infection.
MUTATIONS: Nanomachines don't mutate recoms, in the comic-book sense of the word 'mutate'. Prior to the Apocalypse War, medical nanotech was available that could re-sculpt a humanoid body and change its exterior appearance (including apparent gender). Dr. Soliero was the expert on the history of this particular form of medical nanotechnology. It was possible, pre-War, to alter someone intentionally in a controlled setting (i.e. hospital or laboratory), but due to the loss of critical knowledge in this field, the technology is unreliable, dangerous, and out of reach of the general population.
Because of the enormous power of pre-War medical nanotech and the many mysteries surrounding Earth, many recoms today (incorrectly) believe that Earth harbors 'mutagenic viruses' or combat nanosites capable of purposeful transformation. Stories suggest that some unwary visitors to Earth are traumatically transformed in gender, species, or shape and often die in the process. Movie producers and those responsible for enforcing the quarantine of Earth are no doubt happy that such things live on in the public imagination.