About table summary in HTML5 and HTML4

About table summary:
The HTML5 draft advises  one to design a data table in a manner that it is understandable so that a summary is not needed at all. In fact most complex data tables can be broken down into simpler ones that are easier to understand. While this cannot be faulted generally, one has to admit that complex tables do have value in representing data relationships across dimensions efficiently. And complex tables are not going to go away. Sighted authors and users of tables  may consider a description of the manner in which a table organizes and represents data as a waste of space and time and may choose not to have such a description. That is their prerogative. It is precisely in these circumstances that the HTML 4 summary attribute helps non-sighted users. Likewise, a summary may help non-visual users grasp the design of the 3-column simple moods-table in the HTML 5 draft. Sighted users may find the description unnecessary. A standard cannot mandate that such
 descriptions (or even a caption for a table) should be visible text without impinging on the author’s freedom.
So what is the objection to the HTML4 summary attribute? This remains unclear.
Authors even today are free to include extensive  description of the table’s structure and  a summary of the data (highlights / key values) within a paragraph for all to see if they choose. So I do not understand what is new in the HTML5  draft about using a p-tag to hold such text? Except that it is within the ‘caption’ element. Which I think is weird. As an author I would perhaps want the descriptive text before or after the table and not right after the title. And if a caption is meant to serve as a title or header for a table, how does  a description of the table’s structure or content belong to the caption? 
It is not clear to me from the HTML 5 draft if the contents of the “detail”  or “summary” element is visible  or not. It appears someone is getting a kick out of calling the ‘summary’ attribute by another name or replacing an attribute with an element.

Priceline.com even now uses a summary attribute for the table that displays the results of a search for flights. In May 2004 that summary was much longer. It is included as one of the  examples in the attached htm file. (I had suggested then to Priceline that the table is much too complex and it needs a summary). 

Then here are a couple of links to my posts on the topic: 
http://lists.w3.org/Archives/Public/w3c-wai-gl/2004AprJun/0823.html
http://www.accessifyforum.com/viewtopic.php?t=4336
http://webaim.org/discussion/mail_thread?thread=3992

And here is an observation by the late John Slatin (Dec/2003) to one of my posts on table summary.
I agree very strongly with Sailesh.  The <caption> provides a title for the table and is  available to everyone. The summary makes it possible for blind users to gain information  about the table organization or content that is readily available to people who can see the  table—blind users often have to listen to the table for quite a while in order to gain the  same understanding.
The summary would work well in the example cited—the of checkboxes by hotmail (and other  Web-based mail applications like Yahoo and Webmail) to mark messages for deletion or some  other operation--.  It would be even better if the subject field for the message was  associated with the checkbox via the <label> element. (So this example involves techniques  for tables and techniques for forms.)
John
-----Original Message-----
From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On Behalf Of Sailesh Panchang
Sent: Tuesday, December 02, 2003 3:43 PM
To: w3c-wai-gl@w3.org
Subject: Caption and Summary : [techs] Latest HTML Techniques Draft
Ref: http://www.w3.org/WAI/GL/WCAG20/WD-WCAG20-HTML-TECHS-20031104.html
The tech doc has always maintained that "It is rare to use both the caption element and the  summary attribute (in a table) since one or the other should be enough to provide a  description."
Comment:  It is a good practice to  have captions for all tables as it is like a table  heading and is visible to all. But the summary is not displayed on screen and is especially  meant to provide additional cues  for orientation / navigation to non-sighted users. For  complex / large tables   and  tables that use row/column spanning, useful info can be  conveyed through the summary  attribute. There are many times when both attributes  are  complementary  to each other and the HTML tech doc should not suggest that it is rare to  use both. In fact  the doc should suggest that one should  make the assessment for each  table   on a case by case  basis.
Take for instance even a simple table with 6 columns that lists e-mail messages by rows.  Let's say the first column contains   a checkbox for selecting messages. It is useful if  the captionsays "Sent Messages Folder"  and the summary says "Use the checkbox in the first  column to select   / unselect the message in the respective (or corresponding?) row".
I figured this out myself  on the MSN-Hotmail site that uses this design. A table caption  and summary   would make life simpler in this context for instance.
I have pointed this out to MSN Support too. 
===
Sailesh Panchang (MS, ASQ-CSQE),
Accessibility Services Lead
www.deque.com
Tel 571-344-1765 (C)
703-225-0380 (ext 105) (Work)