Adobe releases the source for its ActionScript Virtual Machine to the Mozilla Foundation

From Penguin.SWF:
Today, Adobe released the source for its ActionScript Virtual Machine to the Mozilla Foundation.
That's what Adobe did. Since this blog is a common stop for open source-minded folk, I thought it might be pertinent to use this space to discuss what Adobe didn't do:
* Adobe did not open source the Flash Player.
* Adobe did not incorporate the Flash Player into Mozilla.
* Adobe did not license Mozilla's HTML rendering engine.
* Adobe did not purchase Mozilla, or vice versa.
The new project will be called Tamarin and will be hosted by Mozilla. From the FAQ:
The goal of the “Tamarin” project is to implement a high-performance, open source implementation of the ECMAScript 4th edition (ES4) language specification. The Tamarin virtual machine will be used by Mozilla within SpiderMonkey, the core JavaScript engine embedded in Firefox, and other products based on Mozilla technology. The code will continue to be used by Adobe as part of the ActionScript Virtual Machine within Adobe Flash Player.
So, what does this mean? Basically, “ActionScript” is based on the ECMAScript language specification which is also the base of JavaScript. With the release of Flash 9 (beta now available for Linux) Flash now uses the ActionScript Virtual Machine to interpret ActionScript in a JIT manner. It's that bit of code that has been Open Sourced and donated to Mozilla. The Tamarin code will be now included within SpiderMonkey, the open source C-based JavaScript engine used by Firefox and other applications based on Mozilla technology. In the end the benefits of this should be significant (although a ways off). Javascript should be much faster and memory efficient once this is integrated, which means AJAX applications will be able to do things that aren't viable right now. Additionally, since much of Firefox itself is in XUL, this could even mean that Firefox itself gets a performance boost. Additionally, from a mindshare perspective this is the largest code contribution that Mozilla has ever received. That goes a long way. Further versions of Tamarin will be shared by both Flash and Firefox, with no fork between the two planned. With no real downside, this announcement should gain Adobe some points in the community, which they need. I suspect this isn't the last time Adobe warms up to the Open Source world. From what I've seen recently they have some pretty large aspirations and Open Source will aide them in much of what I think they want to accomplish.
–jeremy
Adobe, Firefox, Mozilla, Open Source, ECMAScript, Flash, Tamarin