The problem isn't so much that Wiiconnect24 generates a lot of heat so much as the fan is never active when the system is in sleep mode. The problem is, closed space + constant heat + little airflow. It doesn't much matter how little heat it generates it will keep building and heat is the natural enemy of any electronics.
My advice, if you're only gonna use your wii every few days, turn Wiiconnect24 off while in standby, it will help your wii survive longer. If you play actively like everyday, then chances are it won't really hurt you. Actually when I left wiiconnect on 24/7 it ran cooler when I played the wii then when it was in sleep mode which I thought was funny but it also caused me to just turn it off.







