In China, there's a popular online [free] computer game called: "Popkart". I personally play it all the time. You can play against about 8 other racers, and free patches/updates are applied overtime accordingly. It's actually quite impressive: there's chat rooms, a banking system, game houses, huts, inventorys, shopping malls etc. You can buy items, trick out your popkart, and even send gifts to people. There are also passports, that when purchased, allow you to access more/harder race tracks.
What I'd like to see happen, is a very much similar concept with Mario Kart Wii. Like Popkart, in Mario Kart, you should be able to continue racing online against other players [for gold coins]. Which you then use, to buy various virtual goods: a new cart, helmet, masks, teddy bears, bumper stickers, passports etc. [not neccessarily teddy bears, but by example, if your using Diddy Kong you could decorate your Kart with 1up Balloons - red/green/blue. This would allow players to have something to continue to endeavor and work for. It makes the overall concept much more enjoyable [and fun].
In general, you do need to quote/unquote, be able to read Chinese to download Popkart, but I'll show you the website anyway, as it's got the "Popkart-esk" cartoony look to it. But you can also make a good interpretation, as to how well it's been developed. It's actually quite submerssive in my opinion. Outside of Popkart, there's no need to chat online with programs like MSN, Yahoo, or AOL IM - you just "race".
http://popkart.tiancity.com/homepage/