I told you so...
Flex / Apollo is useful for pushing the current browsers to the next level.
Air (nee Apollo) still appeals to me more than Prism. Neither are perfect, yet everyone is heading in a good direction.
Unlike Adobe AIR and Microsoft Silverlight, we’re not building a proprietary platform to replace the web. We think the web is a powerful and open platform for this sort of innovation, so our goal is to identify and facilitate the development of enhancements that bring the advantages of desktop apps to the web platform.I don't know much about silverspoon, but air is not intended "to replace the web". You can build very-much-on-the-web systems with it.