Anyways, I connected my Wii to Wi-Fi, updated it, and downloaded the two new channels: Internet (actually not new, but didn't come with the console) and the Everybody Votes channel.
And now that I can send messages online, I ought to give my friend code: 0123 7218 1455 2464. However, I'm not sure how exactly Wii Friend Codes work.
Finally, although the other channels work quite well, I can't seem to enter the Voting Channel, not even by switching my home country to USA (which I did to enter the Shop Channel