Worldwide software as a service (SaaS) revenue is forecast to reach $7.5 billion in 2009, a 17.7-percent increase from 2008 revenue of $6.4 billion.

According to research Gartner, the market will show consistent growth through 2013 when worldwide SaaS revenue will total over $14 billion for the enterprise application markets.

“The adoption of SaaS continues to grow and evolve within the enterprise application markets,” said Sharon Mertz, research director at Gartner.

Mertz said the 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.

The content, communications and collaboration (CCC) market and the customer relationship management (CRM) market continue to have the largest amount of SaaS revenue across market segments, with the CCC market generating $2.6 billion in 2009, up from $2.14 billion in 2008 and the CRM segment generating $2.3 billion in 2009, up from $1.9 billion in 2008, the report indicated.

SaaS has continued to represent a key driver of growth in the CRM market for the past four years, climbing from less than $500 million in 2005 and over 8 percent of the CRM market to over 20 percent of the market in 2008, with nearly $1.9 billion in revenue.

Gartner said it expects growth to continue, with SaaS representing almost 24 percent of the CRM market’s total software revenue in 2009.

“The rapid adoption of SaaS and the marketplace success of salesforce.com have compelled vendors without an on-demand solution to either acquire smaller niche SaaS providers or develop the solution internally in response to increasing buyer demand,” said Mertz.