Flash vs. Silverlight
Flash and Silverlight can play multiple roles within an organization, so let's start by identifying those. First is the video-player role. For example, if you want to add video to an existing website, you can choose either a Flash solution, which involves the Flash Player playing back either VP6 or H.264 video, or a Silverlight solution, with the Silverlight player playing back Windows Media Video or VC-1.
Figure 1. At first glance, you'd think this site was a Flash site, but it was produced with Silverlight.
Just to be clear, Silverlight is an alternative to Microsoft's Windows Media Player, which could also be used in the video-player role. However, as a browser plug-in, Silverlight has a much smaller download profile (around 4MB) and superior cross-platform support. Like the Flash Player, the Silverlight player can only play media from a website, not content that's already on your hard drive. For this, you'll continue to need the Windows Media Player for Windows Media content and the Adobe Media Player for Flash content.
The second role these technologies play is as a development environment for websites — including a player for rich Internet applications (RIA), which I describe later. In this role, the development environments for Flash and Silverlight are alternatives to HTML for website creation, especially for the media-rich websites that Flash has become known for. For example, Figure 1 is a screenshot of Entertainment Tonight's website for the most recent Academy Awards. At first glance, you'd assume that it was designed in Flash, but it's actually a Silverlight site. You can see more sites designed in Silverlight by visiting silverlight.net/showcase.
Figure 2. The Seattle SuperSonics' website is an all-Flash site.
Third is the streaming server/player role. To access features such as digital rights management (DRM), multicast, or live streaming, web producers need to pair a streaming server with the player. In this section, I'll evaluate the server-related functionality of the two technologies.
Let me start by describing the approach I took to researching and writing this article. First, I had lengthy conversations with product managers from both Adobe and Microsoft. Both companies supplied technology references who I spoke with while writing this story. For broader perspective of more strategic issues, I spoke with colleague Tim Siglin from streamingmedia.com, whose article “More Flash Brings More Light” is a great overview of Adobe's and Microsoft's battle for ownership of rich-media applications.