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

[Scott Reynen]

On Apr 25, 2006, Tantek Çelik wrote:

> We *want*
> resources that can be identified by network location and thus a  
> system that
> shows a bias *for* that is a *good* thing.

Is the proposal that UIDs SHOULD be URLs or UIDs MUST be URLs?  If  
it's MUST, that would seem to discourage use of microformats to  
markup content that doesn't exist at a canonical URL.

>> many well-established identifiers are not based on URL. e.g. In a
>> typical library application, we really want to identify the books in
>> Amazon and local catalog are referencing same thing,
>
> Ah, you just introduced a new requirement, and perhaps that is  
> where the
> disconnect is.

I assumed the same use case.  This is all I've ever seen UIDs used  
for.  What is the other use case?

> The requirement that we are looking at is: globally unique, that  
> is, two
> *different* events/contacts don't end up using the same UID.   
> That's it.

Couldn't we more simply give each event an ID attribute and  
accomplish that?

>> I have a concern that using URLs as UIDs will prevent them from being
>> globally identifiable,
>
> This is a joke, right?

Requesting feedback and then responding like this just seems mean- 
spirited to me.

> URLs are by design global.  The opposite of your
> concern is actually true: URLs will tend to make UID *more* globally
> identifiable.

URLs are inherently globally unique, but URLs are only globally  
identifiable if people use them like that, and I doubt people will.

>> When Eventful is adding an event already found on Upcoming, I
>> would expect Eventful to be more likely to assign a UID of
>> 123872138623 than http://upcoming.org/event/123872138623/
>
> In speaking with both the Upcoming developers and the Eventful  
> developers
> this is not the case.
>
> It is *much* easier and more natural to publish and convey a notion  
> of a
> "permalink" for an event or venue, and then mark that up as its  
> UID, than to
> expose random gibberish UIDs to the user (whether numbers or some  
> other
> opaque sequence).

Right, but one involves pointing to a competitor and the other  
doesn't, and I think that difference has a real-world effect on  
people's behavior.

>> Both Upcoming and Eventful have event IDs that are part of event
>> URLs, but don't associate the events with a particular domain.  The
>> domain association ensures the IDs are unique, but it seems to do so
>> at the expense of identifying multiple copies of the same event,
>
> Not a requirement.  Identifying multiple copies of the same event  
> can easily
> be done by implementations.  E.g. event aggregators can keep track  
> of *all*
> the URLs that an event has when it is found across different sources.

RFC 2445 says UID "MUST NOT occur more than once."  Are we changing  
this in hcalendar?

Peace,
Scott