there could be any number of reasons, but I'll give mine (not saying that it's the same as the OP's). I can't run a dedicated wireless network here because I live on campus, and we are not allowed to "extend" the campus's network. So, I can't have a wireless network running.
My Wii has only a wireless card, and I don't want to spend the money for an ethernet-USB adapter. So what I do, is that when I want to use the Wii online, to download or play games, I turn on internet sharing and share the iMac's ethernet-ed internet connection.
But, in general, anyone with a Wii (which has ONLY wifi internet), and without a wireless network, can use internet sharing from an iMac to create an internet connection for the Wii or the DS or the Ps3 or their iphone.
To the OP: just make sure to turn internet sharing off when you don't really need it. Leaving it on doesn't let the imac go to sleep and keeps it on all the time.
My Wii has only a wireless card, and I don't want to spend the money for an ethernet-USB adapter. So what I do, is that when I want to use the Wii online, to download or play games, I turn on internet sharing and share the iMac's ethernet-ed internet connection.
But, in general, anyone with a Wii (which has ONLY wifi internet), and without a wireless network, can use internet sharing from an iMac to create an internet connection for the Wii or the DS or the Ps3 or their iphone.
To the OP: just make sure to turn internet sharing off when you don't really need it. Leaving it on doesn't let the imac go to sleep and keeps it on all the time.