This week Salesforce.com will, in the words of one industry analyst, "extend the value proposition of software as a service" when it introduces Visualforce at its Dreamforce Conference in San Francisco.

The Visualforce layer introduces the user interface as a service. Visualforce is the latest component of Salesforce.com's Platform-as-a-Service, which the company announced earlier this summer as Force.com. Other components include the database and logic portions.

Visualforce will allow Salesforce.com customers to design custom application interfaces while incorporating other technologies such as HTML, AJAX (Asynchronous JavaScript and XML), and Adobe Flex.

The company made the move following requests from customers who wanted to present a more diverse UI, rather than creating applications that had a similar look and feel to the Salesforce.com CRM, according to Ariel Kelman, senior director of platform product marketing at Salesforce.com.

Doug Menefee, CIO at The Schumacher Group, sounded quite enthusiastic about what he could do with Visualforce, although he hadn't used it yet.

"By being able to build applications utilizing Visualforce, we will be able to build custom interfaces that improve workflow and productivity for data-entry-intensive job functions," said Menefee.

Menefee was also pleased about the opportunity to build wizards in Visualforce.

According to Jeff Kaplan, managing director of THINKstrategies, with each user conference, Salesforce adds another layer of value to SaaS (software as a service).

Up until now, customization has been a thorn in the side of SaaS. It has been a topic of concern and criticism by SaaS skeptics, said Kaplan.

"This new feature and capability is a clear indication of how quickly the SaaS industry is evolving to permit customization. And it is another example [of] how those misconceptions of the past are continually being eroded by these developments," Kaplan said.

Menefee said that Visualforce will allow his organization to apply best practices to user interface design in various applications. This, in turn, will let them customize the employee experience based on their needs for data entry or viewing.

Visualforce uses a "page-based model" built on current Web presentation technology and adds a component library for incorporating common interface elements.

The UI platform tool leverages the data, logic, and workflow capabilities found in the greater Force.com platform.

Among the features included in Visualforce are the following:

• Pages, which allow developers to create pages using standard Web technologies.
• Components, which allow companies to assemble current user interface elements in a new UI.
• Logic Controllers for creating user interface behavior.