Worldwide software-as-a-service ( SaaS) revenue within the enterprise application software market is forecast (http://www.gartner.com/resId=1393813) to surpass $8.5bn in 2010, up 14.1% from 2009, says analyst Gartner.

The rapid adoption of SaaS has contributed to growth in varying degrees across the enterprise software markets, said the analyst. It said there will be a shift in total SaaS revenue from just over 10% of the combined markets in 2009, to more than 16% of combined markets in 2014.

Gartner analyst Sharon Mertz said, "After a decade of use, adoption of SaaS continues to grow and evolve within the enterprise application markets. As tighter capital budgets demand leaner alternatives, familiarity with the model increases, and interest in platform as a service and cloud computing grows."

Mertz said the most widespread SaaS use was in applications with common processes, among distributed virtual workforce teams and within web 2.0 initiatives, although its use was continuing to widen.

Gartner estimates that 75% of the current SaaS delivery revenue could be considered as a cloud service, and that could exceed 90% by 2014 as the SaaS model matures and converges with cloud service models.