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Re: Marking up links to alternative versions of content (was: Re: conflation of issues or convergence of interests?)

From: Henri Sivonen <hsivonen@iki.fi>
Date: Tue, 31 Jul 2007 10:30:46 +0300
Message-Id: <CF047A8A-37A8-479F-A5A4-C96F053F4661@iki.fi>
Cc: public-html@w3.org
To: Sander Tekelenburg <st@isoc.nl>

On Jul 31, 2007, at 06:07, Sander Tekelenburg wrote:
> At 12:27 +0300 UTC, on 2007-07-30, Henri Sivonen wrote:
>> On Jul 30, 2007, at 03:32, Sander Tekelenburg wrote:
> [re: <http://lachy.id.au/dev/presentation/future-of-html/>]
>>> I can consume both the
>>> text and the audio, but only deduce that they're equivalents by
>>> consuming
>>> both. There is zero indication that they are equivalents.
>> The simplest possible way of addressing this issue without needing
>> any changes to HTML and without any new browser UI would be adding a
>> sentence immediately after the links to slides and the audio and
>> briefly state what information they provide that isn't on the
>> transcript page.
> {frown} The point of the example was that the audio and text are  
> equivalents.
> If there'd be a need to explain what one contains that another does  
> not, then
> they are not equivalents.

The premises of my thinking aloud were:
  * Different versions of a work are rarely *truly* equivalent unless  
the difference is only about video or audio codec.
  * Prima facie I don't trust a simple declaration on the markup  
level can provide me with the kind of information I need to choose  
from different versions that I am able to consume at least partially.
  * Prima facie, I trust software performing the selection for me  
based on said labeling even less.

Overall, I'm very suspicious of the whole concept of truly  
"equivalent" content appearing in practice in such a pure form that  
removing the human choice of the user were a good idea (except in the  
case of codecs).

These premises are not based on browsing with AT. These premises come  
from browsing around the Web as a person who can read more than one  
language and view more than one file format.

My distrust of the markup labeling and automatic choice comes from  
translations. I become annoyed when a site offers me a translation  
automatically when I know (or can guess) that the original is written  
in a language that I can also read, because from experience I expect  
to be better off reading the original if it is in a language that I  
can read.

As for file format choices offered by others, I have observed that  
the choice make is not consistent and configurable but depends on  
what I intend to do with the file and what my assumption is about the  
quality of the alternatives based on my guess about the workflow that  
produced the files. When I've offered alternative file formats  
myself, I have found that explaining the purpose of each alternative  
briefly in natural language is the only way that allows the user at  
the other end make an informed instead of having software pick  
potentially an inappropriate version at semi-random.

Now, all the above concerns me making choices about alternatives that  
I could consume *to some degree*. In the accessibility case, the  
usual premise is that the user absolutely cannot consume one version  
*at all* and, therefore, needs an "equivalent" alternative. However,  
it isn't as clear-cut as this. I think it was Gregory who pointed out  
that sometimes it is useful to know what was there even if part of it  
is something one cannot consume. Moreover, there have been  
suggestions that in some cases pieces of content designed to be  
mutually exclusive alternatives should be presented side-by-side  

It seems to me that designing for mutual exclusion, realizing that  
some users want to be aware of the alternatives and then coming up  
with a user interface that presents the supposedly mutually exclusive  
parts at the same time is harder than designing for offering  
alternatives side-by-side in the first place.

> Maybe this is a misunderstanding. I'll assume that in essence  
> you're arguing
> for non-explicit linking of equivalents, as the Subject suggests.

More precisely, I'm arguing that "equivalents" in practice aren't  
equivalent to a degree that it makes sense to hide the existence of  
alternatives from a human and then a human is better off making a  
decision based on human-to-human use of language.

> [1] No program could make use of that.
> - Not an indexing bot.

Making sense of content without explicit associations is the core  
competence of successful search companies.

> - Not a tool that helps authors judge the universality/ 
> accessibility of their
> document.

I'm a developer of a checking tool (not specifically for  
accessibility) myself, but I think that features should be designed  
to suit the communication of authors and users first and machine- 
checkability should come second instead of being a design constraint.  
The checker should work for the author instead of the author working  
for the checker.

> - Not an authoring tool that needs to help the author to not mess  
> up what a
> previous author carefully added to try to help certain accessibility
> situations.

One of the advantages of prose and plain links is that a  
collaborating author can perceive them and not mess them up the way  
"invisible metadata" can be easily be messed up.

> [2] Considering humans: what you suggest provides far less  
> usability than
> explicit markup, because without explicit markup a UA cannot provide
> consistency across sites. Even for people who can consume all data  
> it would
> still mean that the 'mechanism' to determine equivalence is  
> different for
> each site. So a non-explicit solution doesn't address universality.

Based on my own preferences when it comes to choosing from  
alternative language versions, I assume that UA-side consistency  
doesn't model the actual human needs for choice as well as context- 
specific "dumb" links. That is, I'm saying that I assume that  
designing broad enough UA-side UI for exposing alternatives in a way  
that enables informed choice on all sites is much much harder than  
providing two or three links that make specific sense on the site  
they appear on.

> [3] Considering how non-explicitness doesn't address certain specific
> accessibility situations. I believe Gregory already laid those out  
> earlier.

This is why I said that the natural-language description of the link  
should be in the immediate vicinity of the link (in logical reading  
order--not just in visual layout).

>> Would an expression in markup capture (in a way the UA can
>> reasonably expose--even in the usual visual CSS situation) the reason
>> *why* the author thought it was worthwhile to provide non-text
> I'd have to think about that. I thought that so far we were only  
> discussing
> how to allow authors reliably communicate *that* speficic things are
> equivalents. Is there really a need to know why 1 or more  
> equivalents were
> provided?

Yes, since as a user I don't trust that they are truly equivalent if  
there's more than one thing, so I want to know a word of two about  
what and why.

>> (to a
>> degree sufficient for the user to make a decision on which version to
>> get or to figure out what (s)he is missing)?
> I can't follow. If they are equivalents, and explicitly marked up  
> as such,
> the user knows he isn't missing any content by picking any  
> equivalent over
> another.

My point is that a user cannot trust that they indeed are equivalent.  
It is quite reasonable to expect that one version is primary and  
other versions are out-of-date or otherwise second-rate.

> We're talking about making it possible for users to pick their  
> preferred
> equivalent, because they themselves are in the best position to  
> make the best
> choice for them.

That's what I'm saying. And for the *user* to make the choice (as  
opposed to the server or user agent silently making the choice *for*  
the user), I'm arguing that a human-to-human piece of natural  
language description of the alternatives communicates the basis of  
the choice better than machine-readable labels.

> I don't understand what need there might be for them to know
> why a specific equivalent was provided. If anything, they can  
> safely assume
> that it was provided for their convenience.

Actually, I think it isn't safe to assume that an alternative version  
is excellent for the user's convenience and not a second-rate token  
gesture. If I want to find out about a French product, I start with  
the assumption that English-language product information has some  
errors and the information provided by a Finnish importer lacks at  
least 50% of what I want to know. And in theory my personal order of  
preference of languages should be exactly the opposite. From time to  
time the pessimistic assumption does not hold, but I wouldn't trust  
software to figure out when it does and when it doesn't based on  
machine-readable content producer-assigned labels.

Henri Sivonen
Received on Tuesday, 31 July 2007 07:31:12 UTC

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