I know that on HN a majority are on Mac or Linux, but Windows is still a big platform. But yes, we know it's a major problem and it will be fixed very, very soon.
If you as a timestrained startup start developing for multiple platforms before you've got the resources to do so on the other hand then you have a problem.
It's all about resources and business.
It looks good on the video though, and the few bits of screenshot also look pretty slick.
Did you notice the EyeOS link posted by ErrantX earlier today ? How does what you are doing compare to that ?
I looked at both: EyeOS seems to have some nice apps, but no notion of instant-edit like wikiOS. Personally, EyeOS is just another webOS, but with wikiOS, the wiki-factor might make it into something completely different. Hard to tell how much of a game changer it is.