Everybody knows Apple want to defend its anti-flash program by using this term. Backing up the Open Source while keeping it device Closed Platform. Many developers cursed Apple for this. Well I'm not sure most of the Apple programmer care about this. But before I go nuts with why I am happy with this, I should explain to you what does it exactly means.
Open Source is a very common term. Linux, Java, OpenGL, Blender, you name it. There are hundreds of open source program out there. Basically, its a program which you can access the code and modify it by yourself. There are a few limits according to the license came up with it. Yeah, some Open Source came up with license :) The opposite of Open Source is a Proprietary Source (the term closed source is very uncommon). In order to have access to it, you have to gain a permission from a company/person. Its all about permission, and nothing to do with money.
Closed Platform is very common too. Most people just dont know that their hardware is actually closed platform. Consoles is the best example. If you want to develop a game and want to sell it, it has to pass the Nintendo/Sony/Microsoft censors (or whatever they called it) before you can sell it to public. Iphone do this with its application censorship program. Basically your program has to be reviewed by Apple employee before it can reach the (only) store for Iphone App, Apple Store. The Oposite of closed platform is Open Platform. The PC (yes thats including Mac) is the best example. You can make a program and sell it on your own, without passing any censorship.
Now that you understand the terms, I guess you got the idea what is Open Source Closed Platform means. Apple and Adobe, although they seems to be fine with each other, has a problem about Flash on OS X implementation. Hard to tell who is right and wrong in this case.
Adobe blames Apple for being to strict to its OS source code. They got a point. This isn't new about Apple. They are very strict about their code so Sun gave up optimizing Java and throw the responsibility to Apple Engineers to develop Java on OS X. The same thing happened to OpenGL. But both Java and OpenGL are Open Source, so its no problem to develop both. Flash on the other hand is proprietary. Its hard to find the win-win solution between two proprietary company. However Apple blames Adobe being to lazy to implement in OS X environment. They also got a point. If Adobe can develop on Windows (which is proprietary too), why is it so hard to develop on OS X? And most of OS X engine is powered by Open Source code (eg. OpenGL). So logically, its 'easier'.
But this article is not about Flash on Ipad. Its about Open Source Closed Platform. While many programmer are against it, Closed Platform sometimes can be a good idea for a peripherals. Closed Platform guarantees the program will always work as described on the feature list. It also guarantees the program is not a virus or worm. And in some point, it guarantees the quality of the program will reach a certain point. But the problem for closed platform is it make programmers harder to reach the consumer. It also limit the programmer that can jump in to develop a program. The currently hot anti-flash program on Ipad effectively kills all flash programmer that want to reach Ipad/Iphone user. So to tackle this effect, Apple decide to use Open Source program, so any programmer that want to jump in into Ipad or Iphone wont spend too much resource (yes I mean money). The Open Source also guarantee Apple can keep the quality of the source so it keep running well on Apple environment (and yes, they cant do this on flash and flash is really bad on OS X. Every time I open a flash based website, my computer performance goes nuts. ).
At this point, you should've get the idea why Apple goes Open Source Closed Platform to its product. Yes its irritating for most people, but personally, they HAVE to do that. Not just because flash is bad, but they have to control their peripherals to keep the quality top notch. Microsoft did this for their consoles. So does Sony and Wii. In my opinion, not allowing flash on Ipad is the same as not allowing OpenGL on XBox. And from my point of view, it probably a good idea for now. Imagine if they goes Open Platform and got all the viruses like PCs. Something that end consumer dont want too.