This leaves Adobe in a somewhat awkward position. Firstly, it casts ActionScript back to being a proprietary language. Secondly, it means they have released an extremely valuable chunk of intellectual property (in the form of the Tamarin ES4 execution engine), without gaining the expected benefits for the Flash platform.
So why did this happen? When I heard the news, I analysed it in light of who has the most to gain, and in context of previous discussions / information I’ve read. I guessed that the most likely reason that ES4 was dropped, was due to Microsoft. They would have to either write a new execution to support ES4 (which costs money), or swallow their “not built here” pride to use Tamarin. By crushing the standard they would avoid having to do either of these and take a stab at their rival Adobe by pulling the carpet out from under AS3’s standard compliance. Being that they control 80% of the browser market, they are also one of the few groups that could unilaterally block adoption of the standard (having a standard that’s only supported by 20% of browsers isn’t very useful).
So to me, it looks like a power play by Microsoft. And it seems that I’m not the only one – Hank Williams over at whydoeseverythingsuck.com has written an article mirroring my thoughts almost exactly.
These situations are frustrating for developers (well, for almost everyone, I imagine). Standards bodies are so hampered by politics and corporate interests, but of course they are the lesser of two evils (no one wants to return to the wild west of HTML coding). Almost makes you glad that the Flash player is a proprietary product, eh?
UPDATE: Adobe has just made their public response here. Quite candid, and definitely seems to follow the lines of my speculation with mentions of “a morass of bickering, infighting, and sometimes, out and out name calling”.