There are whitelists motivated by business interoperability , i.e. those providers with which the list maintainer is willing to participate in federated identity transactions, and there are whitelists motivated by protocol interoperability , i.e. those providers with which the list maintainer is able to participate in federated identity transactions. As an example of the first sort of whitelist, Japan's Pookmark social bookmark service lists the OPs it will accept assertions from. While some believe Read More...