Microsoft released a four page PDF on Windows 8 Touch including Guidance, Language, Posture, and Targets.
The PDF is available from Microsoft at this direct link and is also embedded in the remainder of this article for your convenience.
http://download.microsoft.com/download/8/A/6/8A652B51-AF09-4A5A-888C-A0465D00FE5E/Windows 8 Touch Guidance.pdf
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