http://www.intertwingly.net/wiki/pie/PaceRestrictRelValuesForAutodiscovery http://www.intertwingly.net/wiki/pie/PaceRestrictTypeValuesForAutodiscovery
While I definitely understand the rationale behind this, it's unlikely that the spec will actually lead to any change in behavior for the various implementations. Also, if memory serves correctly, media types are inherently case-insensitive. We'd likely be better served to document that as a best practice, the rel and type values should be lower case but that many implementations will typically support upper and mixed case values. - James p.s. I also note that the current HTML5 draft contains an editorial note about needing to say something about the case sensitivity of attribute values.
