Pandora ultimately chose Flash, he says, because it has rich audio playback capabilities built in and fantastic cross-platform support.

"It's identical across all the browsers -- Linux, Windows, Macintosh -- whereas the AJAX approaches are built on JavaScript and DHTML, which are quite different from platform to platform in some cases," he says. While it was possible to create an AJAX application that would work across different browsers and operating systems, Pandora would have had to invest a substantial amount of work to make sure it achieved that same compatibility, Conrad says.

"It becomes very tricky in an AJAX application to get audio playback that's satisfying across platforms," Conrad says. "With Flash, you start with a much more level playing field because the Flash runtime is exactly the same on all the platforms."

Open-source Advantage

After settling on the Flash-based approach, Pandora had to decide how it was going to build its Flash application. The developers had three choices: Build it on the native Flash platform, which is designed more for animators than for programmers; use Macromedia's new Flex platform, which is closed-source software that's similar to OpenLaszlo but a relatively younger technology; or take the Laszlo approach. OpenLaszlo had two benefits: One was its maturity, and the other was the open-source nature of the product, which was very important to Pandora.