… I doubt that future versions of .NET will be supported on versions of Windows older than Windows 7. What is especially important about this is that newly built applications will therefore not work on Windows XP. …
— Joe Stagner (prev MSFT, now Mozilla)
The whole post “What’s wrong with Microsoft?” makes an interesting read. Joe has always been someone whose opinion I value, even more so now he is outside of Microsoft.
See also his recent post “HTML5 App versus HTML5 Page – What’s the Difference?”
Source: misfitgeek.com