A basic intro to microdata and schema.org, along with a new schema.org extension for datasets and data catalogs. "TWed" talk April 4, 2012.

1. Joshua Shinavier
Wednesday Nights in the Tetherless World (TWed)
April 4th, 2012

2. Outline
• rich snippets
• microformats
• RDFa
• microdata
• microdata syntax
• schema.org
• deployment
• mappings, tools, extensions
• the Dataset extension
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3. 3

4. the three syntaxes
• several solutions for embedding semantic data in Web
pages
• three syntaxes known (by Google) as “rich snippets”
- microformats
- RDFa
- HTML microdata
• all three are supported by Google, while
- microdata is the “recommended” syntax
4

5. First came microformats
• microformats emerged around 2005
• some key principles
- start by solving simple, specific problems
- design for humans first, machines second
• wide deployment
- used on billions of Web pages
- usage share was at 94% vis-a-vis competing
formats (before microdata, anyway)
• formats exist for marking up Atom feeds, calendars,
addresses and contact info, geo-location, multimedia,
news, products, recipes, reviews, resumes, social
relationships, etc.
5

6. microformats example
<div class="vcard">
<a class="fn org url" href="http://
www.commerce.net/">CommerceNet</a>
<div class="adr">
<span class="type">Work</span>:
<div class="street-address">169 University Avenue</div>
<span class="locality">Palo Alto</span>,
<abbr class="region" title="California">CA</
abbr>&nbsp;&nbsp;
<span class="postal-code">94301</span>
<div class="country-name">USA</div>
</div>
<div class="tel">
<span class="type">Work</span> +1-650-289-4040
</div>
<div>Email:
<span class="email">info@commerce.net</span>
</div>
</div>
6

7. then came RDFa
• RDFa aims to bridge the gap between human-
oriented HTML and machine-oriented RDF
documents
• provides XHTML attributes to indicate machine-
understandable information
• uses the RDF data model, and Semantic Web
vocabularies directly
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8. RDFa example
<div typeof="foaf:Person" xmlns:foaf="http://xmlns.com/
foaf/0.1/">
<p property="foaf:name">
Alice Birpemswick
</p>
<p>
Email: <a rel="foaf:mbox"
href="mailto:alice@example.com">alice@example.com</a>
</p>
<p>
Phone: <a rel="foaf:phone" href="tel:
+1-617-555-7332">+1 617.555.7332</a>
</p>
</div>
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9. last but not least, microdata
• microdata syntax is based on nested groups of name-
value pairs
• HTML microdata specification includes
- an unambiguous parsing model
- an algorithm to convert microdata to RDF
• compatible with the Semantic Web via mappings
9

10. 10

11. microdata properties
• annotate an item with text-valued properties using
the “itemprop” attribute
<div itemscope>
<p>My name is <span
itemprop="name">Daniel</span>.</p>
</div>
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12. multiple values are OK
• as in RDF, you can have two properties, for the same
item (subject) with the same value (object)
<div itemscope>
<p>Flavors in my favorite ice cream:</p>
<ul>
<li itemprop="flavor">Lemon sorbet</li>
<li itemprop="flavor">Apricot sorbet</li>
</ul>
</div>
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13. item types
• these correspond to classes in RDF
<section itemscope itemtype="http://example.org/
animals#cat">
<h1 itemprop="name">Hedral</h1>
<p itemprop="desc">Hedral is a male american domestic
shorthair, with a fluffy black fur with white paws
and belly.</p>
<img itemprop="img" src="hedral.jpeg" alt=""
title="Hedral, age 18 months">
</section>
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14. global IDs
• items may be given global identifiers, which are URLs
• they may be, but do not need to be Semantic Web
URIs
<dl itemscope
itemtype="http://vocab.example.net/book"
itemid="urn:isbn:0-330-34032-8">
<dt>Title
<dd itemprop="title">The Reality Dysfunction
<dt>Author
<dd itemprop="author">Peter F. Hamilton
<dt>Publication date
<dd><time itemprop="pubdate" datetime="1996-01-26">26
January 1996</time>
</dl>
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15. 15

16. the schema.org vocabulary
• schema.org is one of a number of microdata
vocabularies
• it is a shared collection of microdata schemas for use
by webmasters
• includes a type hierarchy, like an RDFS schema
- starts with top-level Thing and DataType types
- properties are inherited by descendant types
16

17. Why should you use schema.org?
There are several reasons.
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18. current schema.org types
(there are around 300 of them)
18

19. In terms of deployment...
...a few key types stand out.
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20. Top types
type occurrences relative
Product 5001966 0.27689260175
PostalAddress 1437388 0.07956913403
WebPage 1402426 0.07763375119
Offer 1267545 0.07016717684
Book 1111463 0.06152698395
Person 968737 0.05362613587
AggregateRating 780967 0.04323179816
GeoCoordinates 546586 0.03025722678
LocalBusiness 544662 0.03015072039
Article 525487 0.02908925463
Place 490433 0.02714877897
Residence 451652 0.02500198869
ItemPage 421911 0.02335562347
Organization 405876 0.02246797792
Blog 268582 0.01486782772
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21. Who’s using it?
Over 1,000 domains found (through Sindice)
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22. Some early adopters
domain occurrences relative
www.couponcabin.com 3662 0.04400596
www.digifotopro.nl 2852 0.034272255
www.weg.de 2336 0.028071525
futpedia.globo.com 2003 0.02406989
www.the-plug.com 2001 0.024045857
www.virtualtourist.com 1953 0.023469044
gdgt.com 1857 0.02231542
www.notasdeprensa.es 1564 0.018794463
www.libreriadelsanto.it 1294 0.015549894
liriklaguindonesia.net 1274 0.015309556
www.direct2florist.com 1080 0.012978273
www.bluefountainmedia.com 1065 0.01279802
www.alphabetsigns.com 1059 0.012725918
www.tasit.com 1004 0.012064988
www.teachstreet.com 1001 0.012028937
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23. schema.rdfs.org
• maintains schema.org ↔ RDF mappings
- there are mappings for BIBO, DBpedia, Dublin
Core, FOAF, GoodRelations, SIOC, and WordNet
• also provides examples, tutorials, and data dumps
See: http://schema.rdfs.org/mappings.html
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24. schema.org tools
• Google’s Rich Snippets Testing Tool
• schema.org libraries are available in Java,
JavaScript, Perl, PHP, Python, and Ruby
• there are schema.org modules for Drupal, Joomla!,
WordPress, and Virtuoso
• online tools include microdata extractors, generators
and validators
• sindice.com supports microdata
See: http://schema.rdfs.org/tools.html
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25. schema.org extensions
• there are dozens of schema.org community proposals
- they extend existing schema.org vocabulary
• several have already been accepted into schema.org,
incl.
- Job Postings
- IPTC/rNews integration
- User Comments
• others: Comics, Learning Resources, TV and Radio,
Software Application, etc.
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26. 26

27. motivation: open government data
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28. the Dataset vocabulary: types
• DataCatalog
- a collection of datasets
- e.g. the International Open Government Data catalog
• Dataset
- an individual, abstract data set
- e.g. a data set about seismic hazard zones near San
Francisco
• DataDownload
- a dataset in downloadable form
- e.g. an RDF/XML dump of the seismic hazard zones
data set
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29. the Dataset vocabulary: properties
• catalog
- the catalog containing a dataset
• dataset
- a dataset contained in a catalog
• distribution
- a data download for a dataset
• keyword
- the topic of a dataset
• spatial
- the spatial extent of a data set (e.g. United States)
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30. Dataset extension RDF
• the Dataset extension maps to a subset of the Data
Catalog Vocabulary (DCAT)
• many other types and properties are inherited from
schema.org
• collectively, they cover
- around 2/3 of DCAT, and
- around half of the Asset Description Metadata
Schema (ADMS)
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31. Dataset example (microdata)
<div itemscope="itemscope" itemid="http://logd.tw.rpi.edu/source/datasf-
org/dataset/catalog/datasf.org/version/2011-Jun-07/thing_89"
itemtype="http://schema.org/Dataset">
<a href="http://www.datasf.org/story.php?title=seismic-hazard-
zones-"><span itemprop="name">
<b>Seismic Hazard Zones</b>
</span></a>
<div><meta itemprop="url" content="http://www.datasf.org/story.php?
title=seismic-hazard-zones-"/>
<span itemprop="description">The dataset represents the Liquefaction
and Landslide Zones [...]</span></div>
<div><i>Country:</i>
<a href="http://dbpedia.org/resource/United_States"><span
itemprop="spatial" itemscope="itemscope" itemtype="http://schema.org/
Country">
<span itemprop="name">United States</span>
</span>
</a></div>
<div><i>Publisher:</i>
<span itemprop="publisher" itemscope="itemscope" itemtype="http://
schema.org/Organization">
<span itemprop="name">Department of Technology</span>
</span>
</div>
</div> 31

32. Dataset example (RDFa)
<div about="http://logd.tw.rpi.edu/source/datasf-org/dataset/catalog/
datasf.org/version/2011-Jun-07/thing_89" typeof="dcat:Dataset">
<div><b><a href="http://www.datasf.org/story.php?title=seismic-hazard-
zones-">
<span property="dcterms:title">Seismic Hazard Zones</span>
</a></b></div>
<div property="dcterms:description">The dataset represents the
Liquefaction and Landslide Zones [...]</div>
<div rel="dcterms:spatial" resource="http://dbpedia.org/resource/
United_States"><i>Country:</i>
<a href="http://dbpedia.org/resource/United_States">
<span about="http://dbpedia.org/resource/United_States"
typeof="adms:Country">
<span property="dcterms:title">United States</span>
</span>
</a>
</div>
<div rel="dcterms:publisher"><i>Publisher:</i>
<span typeof="foaf:Organization">
<span property="dcterms:title">Department of Technology</span>
</span>
</div>
</div>
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33. Google extracts this data
Item
Type: http://schema.org/dataset
name = Seismic Hazard Zones
url = http://www.datasf.org/story.php?title=seismic-hazard-zones-
description = The dataset represents the Liquefaction and Landslide Zones [...]
spatial = Item( 1 )
publisher = Item( 2 )
Item 1
Type: http://schema.org/country
name = United States
Item 2
Type: http://schema.org/organization
name = Department of Technology
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34. Resources
• HTML microdata
- http://www.w3.org/TR/microdata
• Schema.RDFS.org
- http://schema.rdfs.org
• W3C Web Schemas group (public-vocabs@w3c.org)
- http://lists.w3.org/Archives/Public/public-vocabs
• The Dataset proposal
- http://www.w3.org/wiki/WebSchemas/Datasets
• Rich Snippets Testing Tool
- http://google.com/webmasters/tools/richsnippets
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35. Credits
• word clouds by
- http://wordle.net
• deployment statistics discovered using Sindice and
Sindice4j
- http://sindice.com
- http://sindice4j.googlecode.com
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36. Thanks!
• Tetherless World Constellation
• http://tw.rpi.edu
• Contact:
• josh@fortytwo.net, @joshsh
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