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Subject: Re: Request to register "identifier" relation type
From: Herbert Van de Sompel <hvdsomp@gmail.com>
In-Reply-To: <DEE2ABBF-1146-4E17-875F-3F5EFFB540FB@pobox.com>
Date: Sat, 5 Aug 2017 14:56:59 +0200
Cc: Peter Williams <pezra@barelyenough.org>,
 Geoffrey Bilder <gbilder@crossref.org>, Michael Nelson <mln@cs.odu.edu>,
 Simeon Warner <simeon.warner@cornell.edu>, "John A. Kunze" <jak@ucop.edu>,
 link-relations <link-relations@ietf.org>
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To: Ed Summers <ehs@pobox.com>
Archived-At: <https://mailarchive.ietf.org/arch/msg/link-relations/mu0rX8X6qPYUiY0GGxagtTTVNMc>
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On Aug 5, 2017, at 13:59, Ed Summers <ehs@pobox.com> wrote:
>=20
>> On Aug 5, 2017, at 3:38 AM, Herbert Van de Sompel <hvdsomp@gmail.com> wro=
te:
>>=20
>> The answer is in the I-D and in a blog post that is referenced in the I-D=
. Please have a look.=20
>=20
> I think a crisp one or two sentence reply to Peter's question ought to be p=
ossible. He rightly points out that the shared use of 'preferred' by your I-=
D and canonical could cause some confusion for web publishers. It also begs t=
he question of preferred *for what*.
>=20

Good point. Here's my take on it:
- canonical: preferred for content indexing=20
- identifier: preferred for referencing

> The core issue with canonical seems to be less a matter of semantics and m=
ore a practical matter of web publishers not wanting to assign a canonical o=
r bookmark link to another domain (e.g. dx.doi.org) because of uncertainty a=
bout what this would mean for their Google juice. There is an SEO infrastruc=
ture built up around canonical, which has led to it being used quite a bit.
>=20

Publishers indeed use canonical to point to pages on their own site.  This r=
el type is intended eg for reference manager applications: use the target UR=
I not the context URI in a reference. Our research (referenced in the I-D) h=
as shown that landing page URIs (instead of HTTP DOI) are frequently used fo=
r referencing.=20

> I wonder if rather than adding another link relation to the mix if the HTM=
L folks would be willing to update rel=3Dbookmark to allow for usage with <l=
ink> which ought to make it amenable to use in an HTTP header as some other H=
TML relations are (e.g. alternate). The semantics of bookmark speak directly=
 to the issue of persistence that your I-D seems to be addressing.
>=20

Our I-D acknowledges that the semantics of "identifier" are similar to "book=
mark". But "bookmark" is explicitly not allowed in <link> (and hence Link). O=
ne has to assume there were/are reasons for that choice because other rel ty=
pes declared in HTML can be used in <link>.

> Also, while the name 'identifier' is elegant in some ways, I find it a bit=
 hard to swallow since all link targets are technically identifiers.
>=20

Indeed. Then again, this relation type indicates that the target URI should b=
e used as identifier. We have done several presentations at conferences, wor=
kshops, etc over the past months in which "identifier" was floated. It's bee=
n on the Signposting web site (which has an associated mailing list) for alm=
ost a year, see http://signposting.org/identifier/ . We have not received ne=
gative reactions to the choice of term.  Some implementations are meanwhile a=
lready out there.=20

Cheers

Herbert



> //Ed