Bugwards compatibility

Below is a link to an interesting article about the tradeoff between 
"bugwards compatibility" and adhering to the XML specification.  It 
specifically talks about the Microsoft XML parser in IE, but these issues 
are not specific to Microsoft:

http://www.xml.com/pub/a/2001/09/19/being-too-generous.html

As I've said many times in the past, I think that the right solution is one 
where new features are withheld from buggy documents.  This keeps new 
content utilizing the new features from having bugs associated with older 
versions of software, while not breaking old content.

Rob