Quoted: OMB on Cloud Computing

Government is at the very beginning of the third major shift in computing paradigms with the cloud, following the ages of mainframe and client-server computing ... The global market for cloud services is estimated to be $158 billion this year, growing to $244 billion by 2017. However, federal government spending on the cloud is currently only a small percentage of this, with around $3 billion of its annual $80 billion IT budget spent on cloud services.

Scott Renda, the Office of Management and Budget's cloud computing and federal data center consolidation portfolio manager.  Via GCN.