If the light around the disc drive slot is flashing blue continuously, the reason why it is flashing blue is because the console is connected to the internet. When the Nintendo wii is connected to the internet, it communicates frequently with Nintendo. There are many reasons why the blue light can be flashing, so i have listed the common ones below:
1)Your console is updating its software version, using the internet connection.
2)You have received a message from a friend.
3)Your console is connected to Wiiconnect24, this allows the wii to communicate with the internet automatically and is a feature that allows your wii to receive data 24 hours a day. This can make the console receive data such as receiving special messages from Nintendo about products or offers, news and weather updates.