Image credit: by nolanisan
Last week Yahoo! announced that their search engine would be supporting the Common Tag – a recently released new tagging format for Web pages, to go alongside their Search Monkey functionality. Publishers will be able to use these new semantic tags to make their content more “discoverable, connected and engaging”.
What is a Common Tag?
Tags have been used for a long time to organise content online. However, in the absence of a common tagging format for Web content, the benefits of tagging have been limited. Individual things like New York City are often represented by multiple tags (e.g., “nyc”, “new_york_city”, and “newyork”), making it difficult to organize relatedl content; and it isn’t always clear what a particular tag represents – does the tag “jaguar” represent the animal, the car company, or the operating system?
Common Tags are defined using RDFa, a standard format for expressing structured data within HTML.
It is worth noting that Google recently announced using RDFa tags to help structure its data – although at this time is not part of the Common Tag group.
An example of the Common Tag in use:
Just as you can tag content in other documents by making reference to the URL for the content prior to the rel=”ctag:tagged” attribute, you can use the same mechanism for referencing any section of content by referencing the “id” attribute for the DOM element containing the content in the URL.
For instance, if you had a document which contained two paragraphs using the markup:
<p id="first">Star Wars set a new standard for visual effects in space drama. </p> <p id="second">Luke's interest in his heritage made him vulnerable to the Dark Side. </p>
To indicate that the second paragraph is about Luke Skywalker and not some other Luke, you could tag the content of the second paragraph with the following markup (which could appear anywhere in the document.)
<div xmlns:ctag="http://commontag.org/ns#" about="#second" rel="ctag:tagged"> <span typeof="ctag:Tag" rel="ctag:means" resource="http://dbpedia.org/resource/Luke_Skywalker"/> </div>
Note: By using an absolute URL you could tag the second paragraph from another document.
Find other examples of how the Common Tag can used
Uses for the Common Tag :
// Video content can be tagged for semantic terms, avoiding having to transcript the video and having that content appear on the page
// Image search can become more refined
// Content will not always need to have an instance of every type. E.g. a page about ‘Heathrow Airport’ will not need to contain instances of the terms ‘LHR’ or ‘London Heathrow Airport’ to be able rank for these terms.
Why this may not take off:
// Until there is a CMS that has this type of functionality built in Journalist and Copy Writers may not feel they need to be able to add these tags easily enough to warrant using them. Web Developers may not want to constantly have to change the code of a page template whenever new content is added.
// Would a CMS provider warrant it necessary to build in this functionality if larger sites, e.g. Google, are not using these tags?
