I have seen alot of threads regarding this issue, and here is the answer to it clears up a thread or two.
What is the purpose of the Blue LED light?
The purpose of it is to show you when you have recieved a messege from someone on your friends list.
Will it be on constantly when I receive a messege, or will it blink once and I will never have a clue
It will stay on for 5 seconds, than slowly die out, than after another 5 seconds, it will flash up.
Nintendo should have let it be on when I play a game, what gives?
Well I think it is a great way to let people notice when they have a message.
How does it send a message to me when my Wii is turned off?
Actually, your Wii is never turned off, unless it unplugged of course. On your Wiimote, the power button actually puts your wii in standby mode.
What happens when my Wii is in standby mode?
Nintendo programmed the Wii so when you have an internet connection ready to go, the Wii can receive messeges when in standby mode.
But the blue LED is shiny, I want to see it more often
Go to the friends store and buy some friends ;)
hope this clears up some stuff about the blue LED and stand by mode