This could be viewed as a bug report, from the user's perspective. And I am a user and not a coder or designer for ID (though I am a UX dweeb.) However, from a coder/designer standpoint, this is a feature request, thus posting here rather than as a bug.

The feature is to link comments not to an x,y location on a spread, but to (1) an x,y location within a graphics frame, or (2) for a text frame, to specific text in that frame. Linking to text can be by highlighting the text and then attaching a comment to it. (Deleted text that was highlighted could leave the comment at the place where it was deleted; attaching the deleted text to the comment automatically would be great but hard to code.)

The reason for this is that if you add text or move graphics frames around and then, in the Share for Review Panel, click Update Link, your pins or lines don't point to the original material anymore, and all of those comments on that first version don't make sense any more.

As Alan Cooper pointed out in his About Face 1.0, it is important to conform the user interaction design to the user's mental model. My mental model when I started using Share for Review was that I could edit the document, click Update Link and the existing comments' pins or lines would still connect to the text and graphics, not to an x,y position on the original spread. Maybe for a graphics-intensive single-page ad this would make sense, but not for a magazine article or book chapter, which, after all, is mostly what InDesign is about.

I would suggest an immediate fix to this mental model/implementation model conflict by changing the Update Link button so it archives the original document on the server, with the comments still linking to the (right) original text and graphics, presenting the user with a URL for that, and then putting the new document up at the original URL without any of the original comments, but with a link to the original document/comments.

This would allow time to develop the code to link better to text and graphics within their frames.

It would require a bit of help in the interface for users to develop a mental model of how this works, but would be worth it.

Thank you for listening (reading).