Worldwide software as a service (SaaS) revenue is forecast to reach $7.5 billion in 2009, a 17.7 percent increase from 2008 according to a release from Gartner Inc. The market will show consistent growth through 2013, according to the report.

"The adoption of SaaS continues to grow and evolve within the enterprise application markets," said Gartner Research Director Sharon Mertz. "Adoption of the on-demand deployment model has continued to grow as on-demand vendors have extended their services through alliances, partner offerings, and more recently, by offering and promoting user application development through platform as a service (PaaS) capabilities."