A long time ago I asked if MS could document the error messages that come out of the various parts of BizTalk.

My wishes were granted today, and I have a detailed list of error code/message for all of these below:

RFID: http://msdn2.microsoft.com/en-us/library/bb968047.aspx

SSO: http://msdn2.microsoft.com/en-us/library/bb899027.aspx

EDI: http://msdn2.microsoft.com/en-us/library/bb968069.aspx

WCF: http://msdn2.microsoft.com/en-us/library/bb899069.aspx

This level of detail can be used in so many ways, to provide that detail you never had before.