Cloud Computing is the metaphor for the complex infrastructure available as a service via the Internet. Software as a Service (SaaS, pronounced "sass") typically delivers applications through the browser. This could be just one application (Salesforce.com is by far the best-known example among enterprise applications) but that is being extended to several desktop applications, and SaaS is also becoming common for HR and ERP and others.

Utility computing is a form of cloud computing, already available from Amazon.com, Sun, IBM, Google, Yahoo and others. The original offerings were storage and virtual servers on demand. But now, they are replacing complete datacenters, enabling users to stitch together memory, I/O, storage, and computational capacity as virtualized resource pools available over the Internet.

In the "old" days, huge hunks of software were installed on individual computers as though they were isolated lumps of hardware. "End User License Agreements" (EULA) required users to have a fully paid license per computer. Installation processes, plus regular updates and bug-fixes, were a pain. How many terabytes of packaged software remain dormant on how many computers?

SaaS applications are licensed for use on demand, removing the cost and burden of installed software on every computer. This greatly reduces the ongoing maintenance required for conventional "full" installations, and facilitates central control of all updates and upgrades.

SaaS shifts the burden of installation and keeping an application up-and-running from the user to the supplier. Users can leverage rapid with very little support. Customers benefit from the vendor's latest technological features, without the disruptions and costs associated with software updates and upgrades.

SaaS-delivered software enables end-users to deploy more quickly at a much lower cost - typically 2 to 4 times better than fully installed EULA alternatives.

SaaS and cloud-computing are being adopted by many small and large enterprises, including General Electric, and Procter & Gamble. SaaS is here, and it's the wave of the future.