Software as a service (SaaS), also known as on-demand software, is a direction in application outsourcing that's more than just trendy--it's the future, and to a growing degree, the present of business computing. The Gartner Group predicts that SaaS will experience a compound annual growth rate of 22.1% through 2011 for the enterprise application software markets, more than double the growth rate for total enterprise software. While the benefits of on-demand computing compared to the older model of on-premise computing are impressive-- minimal capital investments in hardware and software, very rapid deployment times, access anytime and from anywhere, minimal operational management required, greater reliability and security, IT resources freed up for more strategic business support-- there are significant differences in the on-demand solutions that are available. If organizations don't understand these differences, and fail to select best-of-breed products, they may be sacrificing critical business functionality for no gain.