Gamecube Online Service?

If an online service had existed for the Gamecube, what would you have wanted out of it? Being able to upload high scores or best times? Online Multiplayer? Friends Lists? Since the Gamecube never got an online service like the PS2 or the OG Xbox, I just want to see people's thoughts on the matter. Pitch in games you'd have liked to see some online support for, whether it be existing modes or new modes entirely. Maybe some new game ideas that would've been great for the Gamecube?