"uid" microformats? (was Re: [uf-discuss] ISBN mark-up)

[Bruce D'Arcus]

On 4/26/06, Tantek Çelik <tantek at cs.stanford.edu> wrote:

> > The naming 'uri' vs 'uid' aside, would it be reasonable to RECOMMEND
> > that a URI is used (thus including URLs) and leaving the door open to
> > less useful ids should people want to use them?
>
> Yes, and I have just added similar details to uid-brainstorming, preferring
> URLs first, then URNs.

I'm glad there's some progress in this discussion, but you're still
trying to come up with a general rule for disparate things.

At the risk of throwing major confusion into this discussion, but with
the thought that it might help clarify things further, I'd like to
whip out FRBR again.

The FRBR model says that when talking about stuff, we can think in
terms of four levels of abstraction; from top to bottom:

1) work - an abstract creation
2) expression - some realization of a work (say, an english language text)
3) manifestation (a physical production, like a book)
4) item - the specific thing you have in your hand or on your screen

URLs are in essence focused on 4; they are about locating items. With
web documents, that URL is in essence equivelant to the manifestation
too. If one wants to get article x, one goes to one particular url. No
problem.

But when we're talking about stuff that exists independently of the
web, this breaks down, which is why the value of more abstract uris
for identification.

If one uses a urn to indicate a book isbn, we are at the manifestation
level, and using that makes it possible to then locate any one of
thousands of individual items,

If one uses an asin to indicate a movie, say, one is identifying the
work level, which can then be used to locate multiple expressions
(theatrical releases, special editions, etc.), whcih in turn can have
multiple manifestations (DVD vs. VHS), etc.

So I'd say that URLs should only be preferred where one is referring
to a particular item whose canonical location is in fact on the web.
E.g. when you have a web resource, use a URL. Otherwise, prefer a urn,
and then perhaps other similar options such as info.

Can we perhaps agree on that?

Bruce