What is Flex? It is a framework of APIs written to facilitate application development on the Flash Player. A wrapper around the Flash Player APIs.
Flex is also a term people used to refer to Flex Builder/Flash Builder. The IDE sold by Adobe to write Flex applications. It is really just Eclipse with a plug-in that Adobe developed. There are other tools (commercial and open source) to develop not just Flex applications, but also pure ActionScript applications. Adobe has never seemed to put big money into its development compared to its other tools like Illustrator and Photoshop. But then lately as I've looked at Adobe apps, it seems like outside of those two, they have not been doing anything dramatic with Dreamweaver or Flash Professional, those seem to be more in maintenance mode than any big development.
As someone who has had great experiences with an open source tool (Blender), I know that it can be done right if led by the right person. But Adobe is releasing it to a group, so who's going to lead?
The real question for me is not what is happening with Flex. It is a good framework, but frameworks come and (look at Flex 3 vs Flex 4). Nor is my question what happens with Flex Builder, anyone who's seen my AS3 videos knows I don't use it exclusively during development. My question is what are Adobe's plans for the Flash Player?
I wanted to title this post "If 3D, then death". When I saw the introduction of 3D support with Flash 11 at MAX I made a joke about Flash must be near death. 3D was introduced into Director when it was near its end. But the Flash Player is still alive and well on hundreds of millions of machines and devices.
This announcement is about something Adobe does not have a knack for, making money on a framework (who does?) and creating software development tools. Where does Adobe make its money? For the first half of its life, Adobe made its money on licensing PostScript. Is that still the case? When I first saw Flash taking over, I remarked that it was like PostScript for the web. It didn't surprise me when Adobe acquired Macromedia.