Rumors around the inter webs are that the MS Silverlight will be going dark after the release of Silverlight 5. Version 5 is to be heading to developers soon, but after that the future does not seems so good. It seems that HTML5 will be taking the place of Silverlight for the usage on mobile devices. Adobe has recently dropped flash for the mobile devices as well.
Why do you care?
Security for said devices can also be standardized for web browsing.
This could all be rumors, but the first posting is coming from a reliable source from a ZDNet blog. Be aware of the possibility and watch the inter webs for more information!