I'm actually quite sad about this. Online is the sole reason I ever played Mario Kart Wii (it's what gives the replay-ability for me), and it's also my only source of practice for offline Brawl tournaments.
Yes, I know Brawl's wi-fi servers suck and it can get to the point where it goes like 3 frames a minute, but it's better than nothing. I can't go to the local Smashfests since they're rather far for me and my parents would not let me out. No one at my school plays Smash (and even then, NOWHERE near my level)... I'm really gonna miss Brawling with my friends and the online tourneys Kels will host. :/
I need to Brawl with you guys again (whether we play competitively or not) before the servers go down. =P
I kind of wish they'd do this like 1 year after Mario Kart 8/Smash 4 releases instead or something.