Re: Request to register "identifier" relation type

Peter Williams <> Wed, 09 August 2017 16:59 UTC

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From: Peter Williams <>
Date: Wed, 9 Aug 2017 10:59:47 -0600
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Subject: Re: Request to register "identifier" relation type
To: Ed Summers <>
Cc: Herbert Van de Sompel <>, link-relations <>, Geoffrey Bilder <>, Michael Nelson <>, Simeon Warner <>, "John A. Kunze" <>
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This discussion has convinced me that no existing relation is a good match
for the proposed semantics. However, i am concerned that the proposed
relation has taken this much discussion to understand. The confusion it
generated here does not bode well for it being used properly by mere

I think a more concrete name would greatly improve the usability. Finding a
more concrete name will be challenging because this relation conflate
several different relationships into a single name. These different
semantics are called out in the I-D in sections 3.1-3.4.

Having multiple relations, one for each semantic, might be another way to
address the usability issues. Some of those use cases seem to be covered by
existing relations. For example, `canonical` seems tailor made for the
"Version Identifiers" use case. For other use cases, such as
"Multi-Resource Publications" and "Persistent Identifiers", there don't
seem to be any existing relations that would work. Relations for those
narrower use cases would be much easier to understand and use.


On Wed, Aug 9, 2017 at 10:17 AM, Ed Summers <> wrote:

> Hi Herbert,
> > On Aug 9, 2017, at 10:35 AM, Herbert Van de Sompel <>
> wrote:
> >
> > * On August 5, Ed Summers posted a question regarding applying
> "bookmark" to <link> to the WHATWG list, see
> 2017Aug/0001.html. There are no responses to this post, so far.
> There have been a few responses if you look at the list of emails for
> August:
> > * On August 9, Ed Summer posted a similar question to WHATWG/HTML
> GitHub, see There is a
> reaction from @annevk who (1) speculates that the reason "bookmark" is not
> to be used with <link> might be in order not to overlap with "canonical"
> (2) suggests the use of "canonical" :-)
> Yes, canonical seems to be the relation that most people are reaching for
> initially. I did myself on reading your I-D. The fact that seasoned hands
> like Kevin Marks and Anne van Kesteren are as well says something.
> > * Michael Nelson has further explored "bookmark" and has confirmed that
> there effectively is a reason for not allowing "bookmark" in <link>. It is
> related to its target use case: surfacing a link for content contained in a
> *part* of a page. Hence, Michael concludes that making "bookmark" usable
> with <link> will most likely not happen. @annevk's GitHub response does not
> seem to contradict that. Michael based his findings on studying
> and
> He
> may write another blog post about this, but, for now, here's how he
> explained on Twitter
> Yes, it looks like that's probably where things will sit. As Anne
> indicated it's likely that rel=bookmark cannot be used with <link> because
> of perceived confusion it would cause with canonical. The semantics of
> parts of pages vs the page itself don't seem terribly significant to me
> from an implementation perspective. Unfortunately 'identifier' will also
> probably cause some confusion as well. As systems that rely on 'identifier'
> get developed that will be something for them to deal with.
> Thanks for considering all the questions and tracking the conversation
> over on the WHATWG list. It speaks to the spirit of what you all are trying
> to achieve with this I-D.
> //Ed