Which Pointer Model?

The OAC model seems to propose, for HTML, an ID-based scheme (OAC Presentation, Slide 19), XPointers for XML, lines for raw text and, finally, the usual pixel-based rectangle for 2-dimensional targets:

http://www.example.net/foo.html#namedSection
http://www.example.net/foo.pdf#page=10&viewrect=20,100,50,60
http://www.example.org/foo.txt#line=1,5
http://www.example.net/foo.xml#xpointer(/a/b/c)

Our own proposal, based on the Adobe Digital Edition schema (and as adopted by Mantano) uses the XPointer shorthand notation for HTML:

http://www.example.net/foo.html#point(/1/1/3/1/1:32)

There is definitely room for improvement (and for a discussion) here. Our goal should be to present a unified method which encompasses video and audio content, too.