“Open” is one of those terms that means a lot of different things to different people. Most should be able to agree, though, that open-vs.-closed is a continuum — shades of gray, not just black and white. A light enough shade of gray is “open”, dark enough is “closed”. The arguments are over where those thresholds lie.
I, for example, would argue that HTML5 is open, and that Flash is not. HTML5 is open, to my eyes, because no one vendor defines or controls either its specification or its numerous implementations. The specification is being written and decided upon by consensus by two standards groups, WHATWG and the W3C. There are critics of the HTML5 spec, as well as critics of the process used to create it and the power vested in WHATWG editor Ian Hickson. But you can’t please everybody. The bottom line is that all five of the top web browser makers — Microsoft, Mozilla, Google, Apple, and Opera — agree that HTML5 is an open spec. There’s not much you can get those five to agree upon.
Adobe’s argument that Flash is open largely hinges upon their having published a specification for the SWF file format, and that in May 2008, Adobe dropped the Macromedia-era licensing restriction forbidding the creation of software to play SWF content. The existence of this spec certainly makes SWF more open than if the spec did not exist. But open enough to qualify Flash as an open technology?
One argument against that would be that even a complete working implementation of everything in Adobe’s published spec would leave you with a Flash player that doesn’t work with much popular Flash content. As Christina Warren wrote yesterday at Mashable:
While Adobe can argue that elements of Flash (through its Open Screen Project) are indeed open source, Flash itself is not an open standard. While Adobe cites some open source implementations in its “truth about Flash”, like Gnash — the open source Flash alternative — those same runtimes cannot achieve parity with the closed-source alternatives because parts of Flash associated with DRM and other content controls aren’t available. Just ask XBMC users in the UK who can’t play BBC iPlayer content anymore.
I believe the same is true for any DRM-protected Flash media, such as Hulu. It’s not just that non-Adobe implementations don’t work, but that they can’t.
But let’s put that aside. I often find it a useful technique to concede a point for the sake of argument and see where that leads. So let’s concede that Flash is “open” because Adobe has published the partial SWF 10 file format spec.
Microsoft published the OOXML file format specs for its Office apps. And not only did they publish the specs, they submitted them to a widely-respected industry standards organization, and now they’re ISO standards.
Adobe’s Flash specs have never been submitted to a standards body, let alone accepted, thus, anyone who argues that Adobe Flash is open would agree that Microsoft Office is even more open.