i have heard from friends and web site rumours that having a exrta fan will brake your wii...im scred to leave the extra fan on for 2 long can someone plz tell me is it alright to leave it on all night and day??
Most likely they mean the fan will fill the Wii with dust.
I wouldn't doubt the fan would wear out soon with constant use.
There are air filter for Wii available on eBay if dust build up is a concern.