This is why Adobe bought Macromedia- They see the future as web-based applications, and they want control the API. Microsoft got to where it was by controlling the API people code in, and the environment applications run. Adobe's showing that they're in a position to control the API for what's next.

This is a very clever move. They're signaling to developers who might be tempted by Silverlight that they are eating their own dogfood on Flex, and betting the farm on their tech.

Given the huge investment that Adobe has in existing desktop applications, the implications of this are huge. Flash/Flex is already a Cross Platform development environment that's installed on 99% of machines.

They're looking to make it a par with Cocoa or .Net in developers minds... And it has a good chance of working.