Let me explain this one: an LED is a light-emitting diode, and is familiar to most people in the form of the tiny blinkenlights festooning nearly every gadget ever made. As it happens, blue LEDs were a serious technological challenge and not available until fairly recently. The moment they became available it sparked a technological revolution as suddenly white light was available from these tiny, extremely economical bulbs, and technologies like Blu-ray could exist. This is a truly great thing, and I therefore love blue LEDs.
The problem is that every gadget manufacturer simultaneously suddenly saw the popular appeal of the intense blue they produced, and now one almost cannot buy a gadget without the things on the front of the device. Why is this a problem? Why has it elicited my hatred? Because they are too fucking bright for their actual purpose and do not inherently communicate anything.
This is very simple. Green means "on", orange means "standby", "charging" or "processing" and red means "off". It's a scheme that has worked for ages and is still employed by responsible manufacturers because everyone who lives near a road with a traffic light understands it.
But now nearly every device has a bloody blue-violet eyeball-tanner instead of a proper status LED. This is particularly galling on audio/video components, where, when watching a movie late at night, it is difficult to see low-level detail on your TV screen because you are blinded by the power lights on your gear rack. I have a USB wall charger that I bought specifically to charge things overnight without the sound of a computer intruding on my precious sleep, and the stupid blue LED on the thing is so damn bright that it's actually possible to read in bed with it on.
Are we all over this new colour yet? I am.