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

[Scott Reynen]

On Apr 25, 2006, at 9:21 AM, Tantek Çelik wrote:

> The closest thing to UIDs that current publishers of hCards are  
> publishing
> are their unique URLs within their sites (e.g. Upcoming and  
> Eventful venues
> and events).

I have a concern that using URLs as UIDs will prevent them from being  
globally identifiable, where using otherwise meaningless UIDs would  
not.  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/

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,  
which I thought was the primary purpose of the UID.  I expect URLs as  
UIDs would allow us to identify the same event from the same site,  
but not across multiple sites because each site will use its own URL  
as the UID.

And in the case of book citations, aren't ISBNs the closest thing to  
UIDs currently published?

Peace,
Scott