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Brain dump on advantages and disadvantages of different types of content

From: Ian Jacobs <ij@w3.org>
Date: Tue, 26 Sep 2000 05:54:24 -0400
Message-ID: <39D07250.9388BC18@w3.org>
To: w3c-wai-gl@w3.org
Hello,

Brain dump for archival purposes on some disadvantages
and advantages of plain text, text-only pages, 
alternative text pages, rich multimedia content, and
dynamic content. Your comments and additions welcome!

1) Plain text (i.e., no markup):

   Advantages: may be rendered by readily available 
               assistive technologies in three modes:
               graphically, as speech, and as Braille. 

   Disadvantages: 
           1) does not support structure, navigation,
              style, and other features that promote accessibility.

           2) Unusable today by deaf non-readers
       
           3) Probably useless to some users with cognitive
disabilities.

2) Text-only pages (may include markup but no audio, video, etc.)

   Advantages beyond plain text: linking, navigation, styling,
              and other processing possible.

   Disadvantages beyond plain text: None?

3) Alternative text-only pages. 

   Advantages: Combined with "primary" pages, may produce an 
               accessible  whole.

   Disadvantages:

       1) Two pages are harder to manage than one.
       2) The world is not binary; people can generally use various
          types of content with differing degrees of success. Pushing
          some content to an alternative text-only page creates
          an artificial dichotomy
       3) You lose fine-grain relationships among content. If, instead
          of knowing that a particular piece of text is an "alt" to
          an IMG element, the only thing you know is that page B is
          a text-only alternative to page A, you build an
information-poor
          Web. 

4) Rich multimedia pages:

   Advantages: When accessible, provide information most users can
          use.

   Disadvantages even when authored accessibly:

        1) May be slow to download (implementation issue, though real).
        2) May be unusable to some users unless there is adequate
           control in user agents to suppress interfering background
           images, etc.

5) Dynamic pages:

   Advantages: Useful for conveying changes in information.

   Disadvantages:
        
        1) May be unusable to some users unless there is adequate
           control in user agents to allow control of the rate of
           change.

        2) May cause problems to some assistive technologies 
           (implementation issue, though real)

Other topics??

 - Ian

-- 
Ian Jacobs (jacobs@w3.org)   http://www.w3.org/People/Jacobs
Tel:                         +1 831 457-2842
Cell:                        +1 917 450-8783
Received on Tuesday, 26 September 2000 05:54:26 GMT

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