There are a couple of interesting developments in our tech area this week.

Alexander Ohlinger at the Ludwug Maximilian University has developed the most sensitive acoustic listening device ever by suspending gold nanoparticles in a drop of water then trapping one 60 nanometre sphere in a laser beam whilst another laser fires rapid pulses at other particles close by.

http://www.kurzweilai.net/scientists-create-worlds-tiniest-ear

Using this technique the researchers claim to have acheived microphonic sensitivities down to some minus 60 decibels - or a level one millionth of that normally detectable by the human ear (not including the Melbourne Audio Club ...)
This makes it the most sensitive form of acoustic detection to date and it is probably only a matter of time before certain cable manufacturers start adopting this tech in order to attempt to differentiate and justify their more extravagent designs.
In the real world the LMU researcers are actually hoping to use this microphony technique to listen to individual living cells and viruses to see how they change as a result of disease et al.

Meanwhile Intel corp is patenting microphone tech for a simple and immediately useful application of hooking up Wi fi devices .
Rather than the cumbersome coding that we in the CE and Home Automation business have become all too familiar with their idea is to replace the manual eight digit code with an automated audio communication scheme.
Using their built in loudspeakers Wi Fi capable gadgets would emit a unique series of sounds to a router equipped with a microphone.

http://www.newscientist.com/article/mg21328476.600-loudmouthed-wifi-devices-could-use-sound-to-connect.html

The router hears the code, verifies the device type, and then automatically enrols it onto the particular wireless network.
The sounds emitted wouldn't be able to travel through walls and could vary by product and type, they could even be synthesised voices a la Steven Hawking ... "are you ready now Dave?" ...