I can imagine OAuth being used to allow Twitter integration, but it doesn't really make a lot of sense as a mechanism to lock down identifiers on a single devic

I can imagine OAuth being used to allow Twitter integration, but it doesn't really make a lot of sense as a mechanism to lock down identifiers on a single device. The point of OAuth is to give a new web app access to data in an existing web app without giving up your password -- instead you enter your password into the original app and the new app is given a token with which to retrieve your data. It makes complete sense for Twitter integration: you provide your Twitter password to Twitter and the iPhone ends up with a token it can use to access/post Twitter information. I'm not sure what OAuth would be protecting when you've got multiple apps on a single device: would a user have a Flurry password that they'd enter into the Flurry app to provide access to the Flurry identifier to XYZ.app? Why would you want to do that?