What it is: You know how a site often says to view its content you must install the latest version of Flash? Soon more sites will be asking you to install Silverlight.
Silverlight was announced in the spring and officially launched last week. Already it's upping the ante in rich-media development -- in August, Adobe announced its Flash video player would go hi-def, a move many saw as a response to Silverlight's capabilities.
Who's using it: Some agencies are experimenting with it, including Avenue A/ Razorfish (owned by Microsoft), which has a team dedicated to learning how to use Silverlight. And a few media companies and sports leagues have adopted it. Major League Baseball Advanced Media uses Silverlight to stream video highlights on MLB.com; Netflix has adopted it to show movies on the PC, and CBS Television Stations is using it for a user-generated-content initiative. MSN's Election Guide was built using Silverlight, and the "Entertainment Tonight" website has relaunched using it.
The competition: The good news is web development could get a whole lot better in the next year. In addition to Silverlight and Adobe's innovations in Flash, Sun Microsystems has launched a similar web development product called JavaFX.
The pluses: Silverlight has been getting props for its ability to stream high-quality video. "Simply gorgeous," raved TechCrunch. A CNET blogger lauded its combination of "very impressive user interaction, streaming video and interesting community features."
The hurdles: Adobe is an entrenched player -- getting developers to switch to Silverlight could be a challenge. Also, before you can view content, you must download the Silverlight plug-inr, which may limit the audience for this platform at least initially.