Being more of a designer than a developer, I've got to admit that the thought of second wind for Flash kind of scares me. I've never liked Flash, mainly because historically it wasn't as "open" as HTML, Macromedia Flash (I know, right) crashed a lot, as well as the general abuse of Flash found all around the web in the late 90's/early 2k.
Anyone willing/able to take my (probably irrational) fear away and tell me why this SWF interpreter is a good thing?
Even though I think this is a cool project, I agree 100% with your fears.
I used to do Flash/Flex/Air extensively, and often preached it to my fellow developers, despite considerable resistance. I argued that SWF was fulfilling the cross-platform promise of applets.
And when Adobe managed to mishandle Macromedia's legacy, I was left with much egg on the face. I don't want to go through that again.
That said, good for Mozilla. They really are running with a ton of impressive open source projects.
No second wind here. Think instead of pdf.js and how it relieves you of the bloated security hole called Reader. PDF is a large format (extensions include SWF!) but pdf.js need not handle all of it to be useful in minimizing Reader activations.
Similarly, Flash is going down, never to come back (thanks, SJ). So Shumway need handle only the tall head, possibly as a previewer if not a full Flash replacement. The long tail is not too fat, but it will require a plugin for the foreseeable future.
In the far future, archeologists will pore over archive contents at the edge of the Beyond, decoding ancient languages including JS and SWF, leery of evil transcendant malware ;-).
Even ignoring the Player / AIR runtime, Flash is a fantastic tool for animation authoring. For example, our game artists use Flash to create SWF clips which we then export and playback with an internal format and C++ engine, supporting a fairly limited subset of all SWF features. This content ranges from UI layouts and transition animations to particle special effects and storytelling cutscenes.
It wasn't hard to write it myself (I'd guess about 40 hours for everything), but if we were going to make HTML5 games, I'd definitely consider this library.
Anyone willing/able to take my (probably irrational) fear away and tell me why this SWF interpreter is a good thing?