Adobe announced last night that they are open sourcing big parts of Flex (scoop by Robert Scoble).
You can see the video interview on Scoble’s blog for detail.
There are two ways to look at this announcement:
1) Adobe is using this as ammunition in it’s war with Microsoft… Specifically to attack Silverlight prior to release.
2) Adobe is refining their business model in this space to focus on Rich Internet Application platforms (Media Server, Apollo) and less on the revenue generated from the developer tools.
While I love the anti-Microsoft hype as much as the next guy… having an understanding of Adobe’s business practices leads me to believe this is more about a refinement of the business model and less a reaction to Silverlight.