Simon brown raises a valid point on the "Spec explanations for Pebble?" thread:
That same paragraph starts, "When an Atom Document is relocated, migrated, syndicated, republished, exported or imported, the content of its atom:id element MUST NOT change.". For me, this paragraph talks about the *Atom Document* moving, rather than the content that it represents (i.e. a blog)."
Perhaps we could add "or its associated resource" after "Atom Document"? Graham