Dublin Core Markup: Specialized Structured Data
In Part One of our miniseries on metadata, we examined Schema.org. In part Two, we looked at microformats. Today, we’ll close this series by looking at Dublin Core.
The Dublin Core Metadata Intiative (DCMI) first began in 1995 in Dublin, Ohio. Since 2000, it has been used alongside other specialty markup languages, such as RDFa.
About Dublin Core Elements
There are 15 base elements in Dublin Core: Title, Creator, Subject, Description, Publisher, Contributor, Date, Type, Format, Identifier, Source, Language, Relation, Coverage and Rights.
There is a Simple Dublin Core Generator for these main fifteen elements on the DC website. You can also find an explanation of how to fill out these values on the DCMI Usage page.
Later, an advanced set of terms was added to extend these basic fifteen. The basic fifteen are referred to as elements, and their extensions are called terms. There is documentation on what these mean on the DCMI Terms Documentation page. There is also a metadata generator for this Advanced Dublin Core on their website.
Dublin Core Example Markup
DC markup usually goes in the head element of the page. Here’s how I might add DCMI to my own home page.
<head profile="http://dublincore.org/documents/2008/08/04/dc-html/">
<meta name="DC.Title" content="Lockedown SEO and SEO - Sacramento Web Design and WordPress Web Design" />
<meta name="DC.Creator" content="Lockedown SEO and SEO" />
<meta name="DC.Subject" content="Web design, WordPress web design, eCommerce website design, web development" />
Does Dublin Core Affect SEO?
Most SEO professionals say DC markup is a nice-to-have, but agree there is no definitive proof that it improves page optimization. While it is easy to implement, the argument is there is potential for keyword stuffing abuse.
Neil Patel of Crazy Egg, KISSMetrics, and Hello Bar fame says Dublin Core is beneficial. SEO auditing service WooRank also says that Dublin Core helps SEO, but then again, they help sell itemized SEO checklists to agencies and clients.
The forums at Moz and Search Engine Journal say Dublin Core is essentially a non-factor. If you do choose to include it on your pages, my advice is to test to see if it makes any difference in the search engine ranking pages, but not expect any changes. The main metadata formats that the search engines seem to favor are Schema, microformats, and OpenGraph.
Why Is Dublin Core Still Used?
Dublin Core is still used in conjunction with RDFa, another metadata initiative that was created to begin building the Semantic Web. While the SEO benefits of Dublin Core are unknown at best, many organizations still require Dublin Core as a requirement for web projects. Many non-profits or government sites fall into this category.
For most business websites, DC markup is something that can be done if everything else on the SEO checklist has been taken care of. If you work for an organization that requires DCMI, then there are ways to deal with including it.
Dublin Core Plugins For WordPress
Dublin Core Metadata is a plugin that focuses only on DCMI. It handles most of the Dublin Core data elements, but it hasn’t been updated in quite some time, and looks like it is unmaintained at this point.
Add Meta Tags focuses not only on DCMI, but also Schema.org and OpenGraph. (Adding OpenGraph and Twitter card data may be redundant if you are already using Yoast WordPress For SEO). The good news, is Add Meta Tags is currently maintained and fairly simple to use.
Aside from these, there are only a few WordPress plugins that provide DC metadata, and most of those have not been maintained in several years.
