Hi,
On Sep 25, 2007, at 17:33, Steven Faulkner wrote:
>At least with alt text, unlike with spam, most uncooperative data
>sources aren't wanting to hurt you. They just aren't going to help
>you. It doesn't make sense to ask those who won't help you to hurt
>you if you have the option of asking them to neither help nor hurt.
from my perspective you are beginning to babble here, i am unsure
of your point.
The point is that if you say that there *must* be alt text, you are
going to get alt text: non-bogus (help) and bogus (hurt). You can't
easily tell which is which, so the bogus text dilutes the value of
alt text as a whole (hurt). The absence of alt text does not help the
way non-bogus alt text helps, but at least it doesn't dilute the
trustworthiness of alt text in general.
>No, I don't think we have yet come to the conclusion that the absence
>of data will continue to be worse than bogus data. This should be
>trivially true: If a consumer prefer bogus data over absent data,
>bogus data can (by definition) be generated out of thin air. OTOH, if
>a consumer prefers absent data over bogus data, telling bogus and
non-
>bogus data apart is harder.
lost me here too I am afraid.
You have less noisy information to draw from if you have (mostly) non-
bogus data and absent data than if you have non-bogus and bogus data
in one mix.
It is easy to take non-bogus data and absent data and produce a mix
of non-bogus and bogus data. Every time you get non-bogus data, you
pass it on as such. Every time you get absent data, you pass on some
bogus data (e.g. the empty string or a random number).
If you get a mix of non-bogus and bogus data and want to separate the
two, you need to do more work less reliably.
Therefore, if there's a choice of former and the latter, you should
want to choose the former.
Only getting non-bogus data is not a real option.
The anomalous part in this case is that notable AT generates bogus
data in a way that is easily worse than the bogus data a server-side
programmer might dare to generate. It doesn't make sense that this
should be the permanent state of affairs.
>AT UAs need to deal with those cases, too, though. The question is,
>really, whether explicit flagging as "critical" has enough value
>compared to falling in the same bucket with lack of alt for unknown
>reason.
It is the spec that is making this distinction of certain images
without alt attributes being "critical content" it makes the
assumption that these can somehow be differentiated from all other
altless images, this distinction is reliant upon authors following
the other recommendations in the spec about how to mark up images,
without them doing this (which as we know is the likely case), then
these magical critical content images will become just more
meaningless noise for the AT UA to filter out as they curently do
(most of the time).
Yeah, that aspect of the spec is questionable *if* there is value in
explicitly flagging "critical" images. Is there?
Your arguments also appears to rest on the assumption that
automated software that outputs images to html is providing the alt
text because the current spec says so, i find this rather hard to
believe as they don't appear to be bothered about many other
aspects of the spec.
Can you speculate why it is done if not for the requirement to have
an alt attribute with *some* value?
--
Henri Sivonen
[EMAIL PROTECTED]
http://hsivonen.iki.fi/
