We'll have to wait and see what gets produced for the game. They've done some
tooltip support JS, which would be quite cool to have on a site, but it's less useful if people would have to manually enter what gear they have.
I realized there isn't an official Blizzard SC2 API, but there is a third party one for getting profiles.
http://sc2ranks.com/api
If someone made that for Diablo 3, it would be really cool to make an OcUK Diablo site where people can see what gear characters have and the like, but I'm sure it will take a while for anyone to produce an API like that if they even do.
If I have time before D3's release, I might put a site together just for people to share keys like the OP if no-one minds. It would be easier for people to add their own keys, and also search and stuff. Then if anyone does make an API, change it so you can view peoples levels, gear etc.
I don't know if I will find time before D3 though, so I'm not promising anything. And my free time after D3 gets released will be significantly less.