defining landmarks

I am a  little confused about what is and what isn't a landmark

in the spec (http://www.w3.org/WAI/PF/aria/#roleattribute_inherits) it
lists as landmarks
    * banner
    * complementary
    * contentinfo
    * main
    * navigation
    * search

in the primer (http://www.w3.org/WAI/PF/aria-practices/#kbd_layout_landmark_XHTML)

it also includes
* article
* log
* status

anyone got a clearer idea about this?
-- 
with regards

Steve Faulkner
Technical Director - TPG Europe
Director - Web Accessibility Tools Consortium

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