Dublin Core

The Dublin Core is a standard that describes metadata or microdata for websites or digital documents. Dublin Core is intended to simplify the reading of metadata. It is often considered as a possible ranking criterion in SEO circles. So far, however, this claim has not yet been clearly established.

Development

Dublin Core has its roots in the Dublin Core Metadata Initiative, short DCMI, which was founded in 1994 in Chicago. Uniform standards for the markup of metadata were finally defined in 1995 at a conference in Dublin, Ohio. These standards were called based on the location of the event, i.e. Dublin Core Metadata.

The aim of this initiative was and is to facilitate search engines in searching for documents by noting key content already in the metadata. The scheme defined by the DCMI quickly spread not only on the Internet but wherever search engines are used to find documents, including libraries, museums, or administrations.

Today, these standards continue to be worked over by of a group of volunteers. The organization consists primarily of various boards (supervisory, advisory board, etc.) and working groups, the “communities.”

Basis

The Dublin Core standard comprises 15 basic elements, the “core elements.” The order of these elements in the source code does not matter. Each of these core elements can in turn be defined with additional fields and thus appear repeatedly. Below are some of the possible core elements:

language: This specifies the language, in which the document will be drawn up, similar to the document type definition.
title: The author specifies the title of the document with this which is often used for listings.
subject: The topic can be defined with the help of key words.
coverage: A document can be locally or spatially defined, for example, with geodata.
description: This field indicates the contents of the document, but may also include a tabular overview.
identifier: This classifies the document, for example, based on ISBN.
format: This explains which programs can be used for display.
type: This is a very comprehensive element, because as the creator of the document you can specify whether it is a movie, a video, text, or software program.
creator: Denotes the name of the author of the document.

The DCMI has released a complete list of current core elements on its website.

Areas of application

The Dublin Core standard for metadata can be used both for HTML documents and RSS documents. The data is additionally marked with DC in the meta-elements field. More categories can be created with DCTERMS, as shown below:

 <head profile="http://dublincore.org/documents/dcq-html/">
   <title>Mein Artikel über tolle Dinge</title>
   <link rel="schema.DC"      href="http://purl.org/dc/elements/1.1/"/>
   <link rel="schema.DCTERMS" href="http://purl.org/dc/terms/"/>
   <meta name="DC.format"        scheme="DCTERMS.IMT"      content="text/html"/>
   <meta name="DC.type"          scheme="DCTERMS.DCMIType" content="Text"/>
   <meta name="DC.publisher"     content="Mr. Ryte"/>
   <meta name="DC.subject"       content="Wiki entry about Dublin Core, adviser"/>
   <meta name="DC.creator"       content="Ryte"/>
   <meta name="DCTERMS.license"  scheme="DCTERMS.URI" content="http://www.gnu.org/copyleft/fdl.html"/>
   <meta name="DCTERMS.rightsHolder" content="Ryte"/>
 </head>

Advantages of the Dublin Core standards

Documents can be more easily classified and read by search engines
The elements are easy to insert into documents
The source code is not affected by Dublin Core elements

Benefits for SEO

The benefits of Dublin Core for search engine optimization is still controversial. It has not yet been clearly established whether a website with core elements ranks better than a comparable domain without the conventionalized meta data. The use of metadata is more likely oriented to the future semantic web, when search engines can read and use such additional information. You can get an approximate idea of the power of the additional information in the code from rich snippets which were introduced by Google. In order for these to be displayed, the appropriate metadata must exist in the source code.