While most people know Flash as primarily a multimedia delivery and development technology for Web sites, it is catching on as a front-end user-interface (UI) technology for business applications, an Adobe manager said Wednesday.

With Microsoft pushing its Silverlight technology as an alternative to Flash on the Web, Adobe has been promoting the use of Flash and its development framework, Flex, as well as the Adobe Integrated Runtime (AIR) -- a companion technology that brings Web-based Flash applications to the desktop -- for use among businesses.

This deployment of a technology whose primary domain has been mostly consumer-facing Web applications is encroaching on the territory long owned by Microsoft and other enterprise software and development-tool vendors.

Adobe's Flash has been making progress against legacy desktop applications -- such as those built in C++ -- although that progress hasn't been widely publicized, said Adrian Ludwig, a group manager at Adobe Systems.

"One of the problems with Flash is people only think of it as being used to do public Web sites," he said in an interview in New York Wednesday. "It's a misconception. A significant percentage of [Flash] applications people are making now are enterprise applications behind the corporate firewall."

He cited as an example an application that Siemens and development partner Thrasys created for Siemen's health information system. The companies created a front-end, Web-based interface using Flash and Flex to unite several back-end applications and streamline how employees use information from different systems.

"Rather than pulling out the back end and starting from scratch, they just replaced the UI," Ludwig said.

Adobe also is using Flex and AIR internally in similar scenarios to unite back-end systems through a front-end interface, said Melissa Webster, program vice president for research firm IDC.

In a recent meeting with Adobe, she said the company showed how it is "eating its own dog food" and using AIR -- which can help bring Flash-based Web applications to the desktop -- as the UI for its own internal applications. The company opted to use AIR for these interfaces instead of Flash so employees can run the applications locally when they are not connected to the Internet, Webster said.

But even if Flash and Flex are getting some attention from businesses, it doesn't mean Microsoft and other vendors that provide software for building business applications should be worried about Adobe taking too much of their business yet.

Al Hilwa, an IDC program director, said that before Flex and its related integrated development environment, Flex Builder, came on the market a couple of years ago, there were "no good development tools to develop Flash applications in a decent environment," he said. So it's natural there would be an uptick in Flash-based business applications now that Flex is available, Hilwa said.

Moreover, rich Internet applications (RIAs) are often still too expensive to produce for an enterprise to justify building them, so technologies for developing them are being used sparingly, Hilwa said. "I'm not seeing [RIAs] on fire" in the enterprise, he said.

Still, Hilwa said that in the future there will be more RIAs based on Flash and similar technologies as employees become accustomed to their use on external Web sites and start demanding better UI experiences internally. "In the long run, enterprises are going to have to spruce up their internal Web sites," he said.