Even if companies decide to entrust portions of their information to the cloud, the single largest obstacle to integration of the cloud to the datacenter is the

Even if companies decide to entrust portions of their information to the cloud, the single largest obstacle to integration of the cloud to the datacenter is the problem of identity. In order to effectively integrate the cloud, users have to have the same identity there as in the datacenter. This is, at present, an unsolved problem, at least practically (there are examples of federated identity systems such as Shibboleth, but there is no generally adopted technology).