Standards are good, and in spite of a few warts, I think XML is a great thing. One of the reason every can agree on XML is that it sits there in plain text for all to see - no backends, no hidden api's, no surprises. The funny thing is, even when everyone agrees to markup their stuff in plain text, it still isn't that easy to get compatibility. Even if you skip the obvious CJK language issues, right to left issues, case sensitivity issues, and decided plain text means a-zA-Z0-9, you still have problems to solve. Case in point the new Longhorn release uses a thing called WVG in the Avalon graphical part. This is obviously closely modeled on SVG (sans some of the more annoying things about SVG it seems, yeaay!). Even though SVG was designed to be as generic as possible, there are decisions built right into it's markup that might not be compatible with other systems. As an example, take the two lines:

WVG : <Ellipse CenterX="30" CenterY="90" RadiusX="4" RadiusY="4" Stroke="red" Fill="red"/>
SVG: <ellipse cx="30" cy="90" rx="4" ry="4" stroke="red" fill="red" />

Probably the nicest thing about .Net is the way it unifies approaches to almost everything, and syntax guidelines are one of those things. Two of the things these guidelines stress are 1) all classes and members should begin with an upper case letter, and 2) avoid abbreviations like they are on fire. So then you have a choice with SVG - compatibility with SVG, or with .Net. The funny thing here, is compatibility is broken before you even get to the first line of implementation, in a way that you really wouldn't expect. You wouldn't have this problem if 'ellipse' was actually a GUID underneath, but then you would no doubt have a host of other compatibility problems with the multitude of languages/systems out there.

Compatibility/interop is harder than it looks I guess : ).

PS: I made an SWF>SVG animation converter in .Net a while back (media format converter plugin) - I would love to see what that does in Longhorn. The problem with SVG as it is now is it can't really keep up. The tweaked format may well allow for faster rendering and animation though, lets hope! It would be pretty easy to get that into WVG format from what I've seen so far...

Hold the press - I just noticed the Avalon stuff runs in Direct3D, and it is compiled. Ok, that might speed things up a wee bit ; ).

Now, how do you get on the Longhorn beta : ).