Would it make sense to have single device with microphones that could detect specific sound (i.e. beep of dishwasher) and also could distinguish it from other specific sound (i.e. beep of washing machine) and than push this as a notification via whatever means (i.e. twitter)? With few microphones it could detect direction of sound and than it could learn which appliance makes which sound.

Not that I see a need for something like this, but existence of such device could deter a bit companies from shoving such things to every appliance.