Cloud Computing on 2010: Why or Why Not?

Studies by numerous research firms find that companies can deliver new applications and services up to five times faster with cloud computing, at costs as low as half those experienced with other technologies. Salesforce.com is touting a "five-minute upgrade," the ability to move users from a failed to a functioning data center in five minutes or less thanks to cloud computing. But confusion over public, private, internal, external and hybrid clouds, virtualization, security, application support and other issues still make many users skeptical about "the cloud." So will 2010 bring some form of cloud computing to your organization? If so, why and how? If not, why not?