Microsoft has this “Silverlight” thingie which is more or less but mainly more a clone of Flash. A fair number of pundits hyperbloviated over it, which reverse-impressed me. Somebody is going to land a punch on Flash eventually, but it’s not likely to be Microsoft.
But Silverlight could well have a significant impact by expanding the toolchest of APIs available to AJAX apps. The way this will work is that Silverlight will expose some potent and obscure new features and then Javascript programmers will write wrappers to make these features optional upgrades to the user experience.
A whacky Silverlight-only upgrade might be the ability to use the LAPACK linear algebra package in Javascript; this would speed math up for users who had Silverlight and otherwise leave them going along at a poky but survivable rate. If faster math was useful enough, it would eventually lead to the feature becoming broadly available. Maybe Firefox would start including LAPACK, for example.
This was the adoption curve for XMLHTTPRequest, which started out as an proprietary Internet Explorer feature and ended up being implemented by every browser.
The key thing is that Silverlight-specific abilities have to be optional upgrades to the user experience, so that the system has graceful degradation in the absence of Silverlight.