Microsoft Silverlight 4 vs Adobe Flash 10.1

HTML5, with its promises of plugin free browsing, a 3D graphics and animation API, built-in video and audio tags, an offline data store, and Web Workers to manage long-running background processes, would seem to spell the end of proprietary RIA (rich Internet application) platforms. But the reports of the death of Flash and Silverlight, as the saying goes, have been greatly exaggerated.

To meet the needs of a continually evolving web, companies like Adobe and Microsoft can enhance their plugins far more quickly than any standards group can push new specs through a committee. Work on HTML5 was first started in 2004, and it isn't anticipated to have actual W3C Recommendation status until at least 2022. The web will continue to change, and it won't be the standards bodies who are leading the way.

Today, the Web Hypertext Application Technology Working Group (WHATWG), a consortium aimed at driving new web standards, can't even agree on which video codecs to support, leaving choices for interoperability to the individual browser makers. Support for the new HTML standard will come in dribs and drabs that only complicate the developer's job. Web content providers and developers of rich Internet apps will continue to gravitate toward the strongest RIA ecosystem: the most complete development toolsets and the most reliable content delivery mechanisms, neither of which are addressed by HTML5.

The richest RIA platforms today (and for the foreseeable future) come from clashing titans Adobe and Microsoft, whose Flash and Silverlight platforms both combine excellent tools for developers and designers, broad client support, strong support for server-side technologies, digital rights management capabilities, and the ability to satisfy use cases as varied as enterprise dashboards, live video streaming, and online games. And each has spawned new updates, to Flash 10.1/AIR 2 and Silverlight 4 respectively, which put them on a near-level playing field. Which one should you choose?