There is an installed base of Dublin Core Metadata. Here I present some statistics from a couple of resources discovery databases we've been working with the last 18 months or so.
They are from:
All the data below contain absolute frequency to the left, and elements together with schemes to the right.
In all of the samples, you find DC metadata in about 1-2% of the pages. I think that is a good figure. Librarians catalogue only a fraction of everything that is printed, so why should people put metadata in every WWW page?
The worst abuse of DC qualifiers comes from the CCP trio (NWI database):
7438 dc.creator.corporatename 5995 dc.creator.personalname 1753 dc.creator 1144 dc.creator.personalname.address 852 dc.creator.address 519 dc.creator.name 498 dc.creator.email 424 dc.creator.corporatename.address 200 dc.creator.homepage 199 dc.creator.affiliation 195 dc.creator.postal
Yes, there are postal addresses out there :( They are not mine, I ensure you. Publishers are more keen on metadata than is creators (NWI database):
24373 dc.publisher 21152 dc.publisher.address 1533 dc.publisher.corporatename 443 dc.publisher.corporatename scheme=SMN 57 dc.publisher.name 15 dc.publisher.postal 15 dc.publisher.phone 15 dc.publisher.email 10 dc.publisher scheme=Postal 10 dc.publisher scheme=Phone 10 dc.publisher scheme=Name 10 dc.publisher scheme=Email
For what I can tell, it is publishers who provide metadata, not the creators themselves ;). There are much more publisher tags than creators. Contributors are rare.
Please Note the scheme=SMN above. Authority control is an issue. It is a functional requirement in many projects that CCP elements get their values from controlled lists. The one above is an example of that.
The publisher field is richer than any of the CCP fields, at least as regards depth of qualificaton. Here you have some interesting examples (EUN database).
3424 dc.publisher 289 dc.publisher.corporatename 182 dc.publisher.personalname.address.postal 182 dc.publisher.personalname.address.phone 182 dc.publisher.personalname.address.homepage scheme=URL 182 dc.publisher.personalname.address.fax 182 dc.publisher.personalname.address.email 182 dc.publisher.personalname 22 dc.publisher.email 15 dc.publisher.address
The dc.publisher.personalname.address.homepage scheme=URL is my personal favouriate. The longest one I've seen ever...
We all agree that the CCP elements need a small, neat, flat, and sort of minimalistic substructure. Perhaps no substructure at all.
Whatever you and I think, the WWW pages out there express a wish for being seen. You want that your information should be seen. You want to be seen yourself. I.e., you want to provide contact information.
People just don't care if it's dumb-down-able or not... And we must do something about this! Possibly, the only way forward in that area might be Tom's proposal of an agent core. Someone must do some real effort to find an acceptable solution for this. It has to be this group of people, hasn't it, if not this group.
Indeed, dc.publisher is about as popular than dc.title. On the Swedish Web, the frequencies of titles and publishers is about the same, was at the time more or less equal to the total number of pages with embedded metadata (NWI database)
24328 dc.title 331 dc.title.alternative 2 dc.title.subtitle 1 dc.title.mainInterestingly number of titles were more twice as large as the number of descriptions (NWI).
10192 dc.description
Here in Sweden, I cannot find any substructure for description. In the educational database I find two encoding schemes (EUN):
2929 dc.description scheme=URL 2791 dc.description scheme=FREETEXT 1141 dc.description
Note the URL as a scheme for the description... For the fun of it, I've made a small exercise to see what encoding schemes you find out there. Earlier today someone mentioned as URI as being permissible for just about every element. They are not really used that way today. Here is a sample of scheme=UR* in my Swedish database (NWI):
7466 dc.relation.ispartof scheme=URL 6581 dc.relation.ispartof scheme=URN 947 dc.identifier scheme=URL 470 dc.identifier scheme=URN 49 dc.relation scheme=URL 25 dc.source scheme=URL 17 dc.rights scheme=URL 5 dc.relation scheme=URN
Most URNs come from a single site, an electronic text archive, and they are genuine. Each chapter/story/poem is pointing to a cover page for the novel or the book it comes from. You may ask about the related issue, the source element. In Sweden it is not used very much (NWI):
861 dc.source 25 dc.source scheme=URL 10 dc.source scheme=ISBN 3 dc.source scheme=ISSN
In the educational database, we find a particularly interesting use of source (EUN):
2581 dc.source scheme=FREETEXT 289 dc.source.title 289 dc.source.date.created scheme=ISO8601 289 dc.source.creator 212 dc.source 1 dc.source scheme=URL
For subject there are a number of schemes out there. A few examples (NWI)
1993 dc.subject scheme=CERIF 452 dc.subject scheme=SAB 122 dc.subject scheme=SABAO 98 dc.subject scheme=LCSH 47 dc.subject scheme=JEL 37 dc.subject scheme=YSAS 37 dc.subject scheme=LCCS 29 dc.subject scheme=DDC 9 dc.subject scheme=LUB_index_sv 1 dc.subject scheme=SABS 1 dc.subject scheme=Freitext
In the educational database I get the following schemes (EUN)
91 dc.subject scheme=DDC 24 dc.subject scheme=GEM 4 dc.subject scheme=ERIC 1 dc.subject scheme=SWD 1 dc.subject scheme=LCC 1 dc.subject scheme=DCC
There is a set of qualified subject tags found in a network of services dealing with environmental data (NWI database):
543 dc.subject.envthreat scheme=SMN 387 dc.subject.sector scheme=SMN 381 dc.subject.nature scheme=SMN 218 dc.subject.general scheme=SMN 182 dc.subject.species scheme=SMN 155 dc.subject.chemistry scheme=SMN 90 dc.subject.envdata.program scheme=SMN 27 dc.subject.miljfrag scheme=SMN 24 dc.subject.envdata.variable scheme=SMN 21 dc.subject.envdata.medium scheme=SMN 18 dc.subject.sektor scheme=SMN 11 dc.subject.naturtyp scheme=SMN 11 dc.subject.allmant scheme=SMN 9 dc.subject.art scheme=SMN 6 dc.subject.kemi scheme=SMN
A better part of their classification system is somehow appended directly to the dc.subject, which means that part of the information is lost when I did the dumb down.
In the engineering database we find interesting developments as regards subjects, with schemes given as URLs, which clearly shows the influence from RDF/XML namespace thinking. These "namespace schemes" are all harvested from sites in Australia:
43 dc.subject scheme=LCSH
39 dc.subject scheme=DDC21,DEFsubject
30 dc.subject scheme=pacs1999
24 dc.subject scheme=DDC
20 dc.subject scheme=MathNet
11 dc.subject scheme=CERIF
9 dc.subject scheme=LUB_index
5 dc.subject scheme=SAB
5 dc.subject scheme=LCCS
4 dc.subject scheme=SWD
2 dc.subject.sector scheme=SMN
2 dc.subject scheme=LCC
2 dc.subject scheme=Environment Australia Thesaurus
http://www.environment.gov.au/library/ea_thesaurus.html
2 dc.subject scheme=DCC
2 dc.subject content= scheme=MathNet
1 dc:subject
1 dc.subject.keywords scheme=Freetext
1 dc.subject.industry scheme=BEP
1 dc.subject.general scheme=SMN
1 dc.subject scheme=keyword
1 dc.subject scheme=http://www.greenhouse.gov.au/nav/thesaurus.html
1 dc.subject scheme=http://www.energystar.gov.au
1 dc.subject scheme=frei vergeben
1 dc.subject scheme=LUB_index_sv
1 dc.subject scheme=Keyword
1 dc.subject scheme=Environment Australia Thesaurus
http://www.environment.gov.au/portfolio/library/work/ea_thesaurus.html
1 dc.subject scheme=Environment Australia Thesaurus
http://www.environment.gov.au/portfolio/library/ea_thesaurus.html
1 dc.subject scheme=DDC21,DEFtid
1 dc.subject scheme=DDC21,DEFgeography
1 dc.subject scheme=BK
When we still did harvesting for the NWI, there were about 6000 unqualified dc.subjects out there in the NWI. In the EUN we see the following
2762 dc.subject.keywords scheme=FREETEXT 922 dc.subject 200 dc.subject.keywords
And in the engineering one.
755 dc.subject 103 dc.subject.keyword
I've only found scheme=FREETEXT in Germany, and most of them in a single site, the Deutsch Bildungsserver.
In the forthcoming specification of DCMI interoperability refiners and encoding schems, we have a particularly rich substructure for Coverage. In Sweden we used to have (NWI)675 dc.coverage.spatial.areaname scheme=SMN 183 dc.coverage scheme=TGN 12 dc.coverage.local scheme=SMN
I know that there are user interfaces in search engines supporting these (I'm providing the TGN one myself), so they are real implementations. The environmental people have their own schemes for coverage, two different for different purposes reflecting the importance of geospatial data for resource discovery when it comes to environmental issues.
In the engineering database I get
197 dc.coverage 22 dc.coverage.placename 20 dc.coverage scheme=Freetext 4 dc.coverage.y.min scheme=DD 4 dc.coverage.y.max scheme=DD 4 dc.coverage.x.min scheme=DD 4 dc.coverage.x.max scheme=DD 4 dc.coverage.t.min scheme=ISO 8601 4 dc.coverage.t.max scheme=ISO 8601 3 dc.coverage. scheme=TGN 2 dc.coverage.y scheme=DD 2 dc.coverage.y 2 dc.coverage.x scheme=DD 2 dc.coverage.x 2 dc.coverage.spatial 2 dc.coverage.campus 1 dc.coverageplacename 1 dc.coverage.z 1 dc.coverage.spatial.areaname scheme=SMN 1 dc.coverage.placename scheme=TGN 1 dc.coverage.place 1 dc.coverage.periodname 1 dc.coverage scheme=LCSH
It seems that we here in Sweden are using Coverage more effectively than in the engineering sites worldwide. The encoding schemes DMS and DD, is no good if you want to repeatable elements.
Speaking about coverage, we have the rich date element (NWI):
4722 dc.date.x-metadatalastmodified scheme=ISO8601 1841 dc.date 919 dc.date.valid scheme=ISO8601 682 dc.date scheme=ISO8601 636 dc.date.creation scheme=ISO 8601 457 dc.date.created 324 dc.date.modified 179 dc.date.creation scheme=ISO31 143 dc.date.current scheme=ISO8601 116 dc.date.current scheme=ISO31 36 dc.date scheme=ISO 34 dc.date scheme=ISO31 26 dc.date.current scheme=RFC822 24 dc.date.creation scheme=RFC822 20 dc.date.creation 19 dc.date.current scheme=ANSI.X3.30-1985 14 dc.date scheme=RFC822 13 dc.date.creation scheme=ANSI.X3.30-1985 8 dc.date.iso8601 8 dc.date scheme=ISO.31-1:1992, Type=Modified 6 dc.date.creation scheme=ISO8601 6 dc.date-x-metadatalastmodified scheme=ANSI.X3.30-1985 3 dc.date.x-metadatalastmodified 2 dc.date.current 2 dc.date scheme=ISO31 Type=Current 2 dc.date scheme=ANSI.X3.30-1985 1 dc.date scheme=ISO6801 1 dc.date scheme=Frei 1 dc.date scheme=ANSI X3.30-1985
Here you find something extremely rare these days. In the data above, you (I repeat it):
8 dc.date scheme=ISO.31-1:1992, Type=Modified
These are the remnants of a metatag of the form
<META NAME="DC.date" CONTENT="(scheme=ISO.31-1:1992)(Type=Modified) xxxxx)">
That is, 8 web pages metalabelled before the DC Down Under in Canberra, where the dotty syntax was proposed by Misha Wolf!
The Date element as used by the educational people (EUN):
3026 dc.date.created scheme=ISO8601 2737 dc.date.valid scheme=ISO8601 2737 dc.date.modified scheme=ISO8601 624 dc.date 290 dc.date.x-metadatalastmodified scheme=ISO8601 289 dc.source.date.created scheme=ISO8601 169 dc.date.created scheme=ISO 31-1:92 168 dc.date.valid scheme=ISO 31-1:92 168 dc.date.modified scheme=ISO 31-1:92 60 dc.date.created 58 dc.date.modified 57 dc.date.valid 29 dc.date scheme=ISO 31-1:92 25 dc.date scheme=ANSI.X3.30-1985 12 dc.date.x-metadatalastmodified 2 dc.date scheme=ISO31-1:92 2 dc.date scheme=ISO.31-1:1992 1 dc.date.validto scheme=ISO 31-1:92 1 dc.date.lastmodified scheme=ISO 31-1:92 1 dc.date.current 1 dc.date.creation
In another database with engineering resources worldwide we get an even richer flora of dates:
925 dc.date.x-metadatalastmodified scheme=ISO8601 270 dc.date 136 dc.date scheme=ISO8601 100 dc.date.current scheme=ISO31 84 dc.date.creation scheme=ISO 8601 82 dc.date.current scheme=ISO 8601 20 dc.date.modified 17 dc.date.created scheme=ISO8601 16 dc.date.lastmodified 15 dc.date.creation scheme=ISO31 13 dc.date.current scheme=ANSI.X3.30-1985 12 dc.date.lastmodified scheme=ISO 31-1 11 dc.date.current scheme=FGDC 11 dc.date.creation scheme=FGDC 10 dc.date.current scheme=RFC822 9 dc.date.modified scheme=ISO8601 9 dc.date.creation scheme=RFC822 9 dc.date scheme=RFC822 8 dc.date.valid scheme=ISO8601 8 dc.date scheme=WTN8601 7 dc.date.lastmodified scheme=ISO8601 6 dc.date.issued scheme=ISO8601 6 dc.date.created 6 dc.date scheme=ISO 8601 5 dc.date scheme=ANSI.X3.30-1985 4 dc.date.issued 4 dc.date scheme=ISO31 3 dc.date.creation scheme=ANSI.X3.30-1985 3 dc.date scheme=ISO31-1:92 2 dc.date.x-metadatalastmodified scheme=ISO 8601 2 dc.date.x-metadatalastmodified 2 dc.date.expires 2 dc.date scheme=ISO 1 dc:date.issued 1 dc:date.created 1 dc.date.valid scheme=ISO 31-1:92 1 dc.date.updated 1 dc.date.revised 1 dc.date.modified scheme=ISO 31-1:92 1 dc.date.modification_of_present_form 1 dc.date.lastmodified scheme=iso31 1 dc.date.lastmodified scheme=ISO31 1 dc.date.creation scheme=iso31 1 dc.date.created scheme=WTN8601 1 dc.date.created scheme=ISO 31-1:92 1 dc.date scheme=iso 8601 1 dc.date scheme=W3CDTF 1 dc.date scheme=RFC882 1 dc.date scheme=ISO 31.1 1 dc.date scheme=ISO 31-1:92
What about the competition? DC metadata is a fairly small fraction of the metadata actually embedded into pages. These are metadata that are frequently added to pages by authoring tools, some of which we used to analyze and map back to Dublin Core:
22742 keywords 20782 content-type 20376 description 9321 author 2135 copyright 1025 publisher 961 distribution 848 resource-type 815 language 590 date 562 title 493 reply-to 447 abstract 445 page-topic 423 owner 412 formatter 400 audience 340 originator
One might perhaps expect a lot of IMS in the educations, but this is not the case, actually.IMS does not appear very often, and only in the educational database (EUN):
344 ims.usetime 344 ims.usersupport 344 ims.type 344 ims.title 344 ims.subject.keywords 344 ims.subject.description 344 ims.structure 344 ims.source 344 ims.rights.userights 344 ims.rights.agent 344 ims.relation.isbasedon 344 ims.publisher 344 ims.pricecode 344 ims.presentation 344 ims.prerequisites 344 ims.platform.requiredsoftware.description 344 ims.platform.requiredhardware.description 344 ims.pedagogy 344 ims.objectives 344 ims.meta-meta-data.scheme 344 ims.meta-meta-data.lastmodifieddate 344 ims.meta-meta-data.containertype 344 ims.meta-meta-data.author 344 ims.location 344 ims.learninglevel 344 ims.language 344 ims.interactivity 344 ims.identifier 344 ims.granularity 344 ims.format 344 ims.date 344 ims.creator
The SAFARI database
7926 dc.title 7926 dc.description 7914 dc.publisher 7898 safari.targetgroup 7736 dc.type 7139 dc.identifier 6441 dc.subject 6318 dc.subject scheme=CERIF 5879 dc.language scheme=ISO639-1 5869 dc.creator.personalname 4945 dc.publisher.address 4042 dc.date.x-metadatalastmodified scheme=ISO8601 3593 dc.creator.personalname.address 2619 dc.format scheme=IMT 2547 dc.date scheme=ISO8601 2145 dc.rights 1425 dc.language 1425 dc.date 1051 dc.creator.corporatename.address 961 dc.creator.corporatename 922 dc.date.valid scheme=ISO8601 689 dc.subject scheme=JEL 647 dc.creator 575 dc.creator.address 542 dc.identifier.url 542 dc.date.current scheme=ISO8601 541 dc.creator.name 442 dc.subject.keywords 392 dc.creator.email 278 dc.coverage. scheme=TGN 227 dc.creator.identifier 185 dc.subject.keyword 106 dc.coverage scheme=TGN 77 dc.date.x-metadatalastmodified scheme=SCHEME=ISO8601 62 dc.date-x-metadatalastmodified scheme=ANSI.X3.30-1985 56 dc.creator.adress 28 dc.safari.targetgroup 22 dc.identifier scheme=URL 17 dc.contributor 13 dc.type scheme=SMN 13 dc.title.alternative 12 dc.subject.sector scheme=SMN 12 dc.language scheme=ISO 639-2 11 dc.publisher.corporatename scheme=SMN 11 dc.date.x-metadatalastmodified scheme=ISO 8601 11 dc.date.valid scheme=ANSI.X3.30-1985 6 dc.subject scheme=SABAO 6 dc.date.creation scheme=ISO 8601 5 dc.subject scheme=YSAS 5 dc.subject scheme=SAB 5 dc.subject scheme=LCCS 4 dc.subject.envthreat scheme=SMN 2 dc.subject scheme=DDC 2 dc.subject scheme=CERIF\ 2 dc.publisher.corporatename 2 dc.language scheme=ISO639-2 2 dc.language scheme=ISO639-1\ 2 dc.format 2 dc.date.x-metadatalastmodified scheme=ISO8601\ 2 dc.date.valid scheme=ISO8601\ 2 dc.date.modified 2 dc.date.created 2 dc.coverage.spatial.areaname scheme=SMN 2 dc.coverage. scheme=TGN\ 2 dc.contributor.personalname 1 dc.subject.envdata.variable scheme=SMN 1 dc.subject.envdata.program scheme=SMN 1 dc.subject.envdata.medium scheme=SMN 1 dc.subject scheme=LCSH 1 dc.source 1 dc.rights scheme=URL 1 dc.relation 1 dc.language scheme=ISO 639 1 dc.identifier scheme=URN 1 dc.coverage 1 dc.contributor.corporatename