The short version of these magic mirrors is that any one magic mirror can make a 2-way connection to any other magic mirror by the user asking their mirror to connect to another mirror by its unique name.
Many of the answers to the monetization question suggest using mirrors to replace wires/fiber-optic cables/radio signals in current communication technology. The magic mirrors as described appear to:
- Not use any power (no apparent power source involved, no apparent degradation from use)
- Not have a limit on range (tested at 1500 km apart)
- Transmit both vision (which we've all assumed means light, the full EM spectrum) and sound in high or perfect fidelity
- Not require an infrastructure like wires or cell towers to carry a signal between mirrors
- Understand natural language in at least 5 languages and presumably any language spoken by a human
- Require a unique name, which can be any unintelligible combination of syllables, leaving an absurdly wide address space.
- Understand and correctly interpret drunkenly slurred as well as computer-generated speech. (They may possibly interpret unspoken intent in the speaker's mind, further testing is required.)
Magic mirrors can be created by an intelligent lay person (possibly on their first attempt; this was unclear) with $50 of materials and equipment in two hours' time. Those costs and requirements leave a huge potential for manufacturing optimization.
The first modern maker of these mirrors, Pavel J., discovered some ancient documents in Baba Yaga's house detailing how to make them. He has created a small number of mirrors and done some basic tests of their abilities. As with any other new technology, there are often limitations and/or drawbacks which are not apparent when the technology is first discovered but which become apparent as the technology becomes widespread. For example, radio signals have a practical limit to how many overlapping signals can exist simultaneously before they start interfering with each other. It wasn't an issue 100 years ago, but it sure is today.
What subtle limitations can be applied to how these mirrors function so that they are still quite useful, but not so overpowered that they turn civilization on its head?
Good answers will have one or more limitation which
- would not be immediately obvious to a lay person testing a handful of hand-made magic mirrors.
- would not curtail the mirrors' abilities so much that they become useless or worthless if patented and mass produced.
- will keep magic mirrors from directly causing modern society as we know it to cease to exist.
- is not easily overcome or bypassed (eg the mirrors output cancer-inducing radiation; easily overcome by adding radiation shielding).
- can't be misused by a mad scientist to easily destroy the world (eg duplicating photons in a loop to instantly create massive amounts of energy from nothing).
- (ideally) resolves magic mirrors initially appearing to break the 1st Law of Thermodynamics. (Note: perfect efficiency is ok, just no energy coming from nothing)
- cannot itself result in destruction of the world as we know it.
Answers will be judged on subtlety, simplicity, and robustness:
- Subtlety - is the drawback difficult to notice in initial tests? Would it have no appreciable effect on ancient usage?
- Simplicity - is the drawback fairly simple to explain and understand?
- Robustness - does the drawback just introduce new plot holes or break physics in new (if interesting) ways?