And what's new is not just self-service management and pay-by-consumption.
While these aspects are still valid, what's really different about cloud computing is the ability to build Internet-scale applications (scale-out, service-oriented, elastic, always-available, multi-tenant, failure resistent, federated, etc.); applications that can service hundreds of millions of users, process massive amounts of data, and participate in the Web ecosystem.
Platform-as-a-service cloud compute environments, like Microsoft's Windows Azure platform (http://azure.com), provides support for applications that operate at Internet-scale, so that companies can focus more on business offerings without investing in huge engineering efforts in their own infrastructure.
The earlier commenters are right, that cloud computing seems "impractical" because of the lack of control, localized hardware, incomparable security, etc. But those things are compromises made in these cloud platforms to enable massive scale.
And thus cloud computing isn't just a different hosting environment for the same things we run now. It's actually more suitable for applications that need massive scale (think social networks, consumer-facing services, etc.), which often aren't as impacted by the different level of support for some of the things we need in our own data center environments.
The best of ZDNet, delivered
ZDNet Newsletters
Get the best of ZDNet delivered straight to your inbox
