Online

[JCpackers05]

ok so if you want to play a friend online do you need there friend code.....so in other words.....can you only play against kids you have their friend codes for

 

[Wishale]

Uhh, Thats the rumour.. But i think they will make it different

 

[The_Mitch]

with some DS games you can choose to play someone via friend code or just get paired up with a random person so they may do it that way on the Wii. no one knows for sure yet

 

[O D S T]

they definately wont do anything stupid like that. I'm sure tehy will have other ways to match up

 

[King Wiired]

Well I heard about it.. but I don't think they'll stick with it

 

[JCpackers05]

good cause that would be so gay

 

[Squall7]

Ok, so I've just read up on how the Wifi works, and there's two modes: Friend codes or Automatch. One allows you to play with specific friends, whilst Automatch allows you to play with anybody else on the automatch mode. My source

Also, Mario Kart has the ability to pitch players against each other based on game data (as in experienced players get matched together, and inexperienced players get matched together).
wikipedia says

That should keep you informed..

 

[Lord Haku]

I think it is true