Semantic MicroformatsSemantic Microformats

Uche OgbujiUche Ogbujiuche@zepheira.comuche@zepheira.com

About the presenterAbout the presenter

XML expert since 1997

RDF/Semantic Web expert since 1999

Web services/SOA expert since 1999

Heavy work with XML and RDF/SemWeb/SOA best practices

Lead developer of key open specs and OSS, e.g.

Versa RDF query language

4Suite XML/RDF processing toolkit

Amara XML toolkit

XML expert since 1997

RDF/Semantic Web expert since 1999

Web services/SOA expert since 1999

Heavy work with XML and RDF/SemWeb/SOA best practices

Lead developer of key open specs and OSS, e.g.

Versa RDF query language

4Suite XML/RDF processing toolkit

Amara XML toolkit

About Zepheira, LLCAbout Zepheira, LLC

Firm offering Semantic technologies solutions bridging technology and business

Team of leaders in next generation Web technology and business applications

Founded in 2007, already featured in MIT Tech Review and BusinessWeek

If you see me in the halls later, ask me about “Zepheira 3D”

Firm offering Semantic technologies solutions bridging technology and business

Team of leaders in next generation Web technology and business applications

Founded in 2007, already featured in MIT Tech Review and BusinessWeek

If you see me in the halls later, ask me about “Zepheira 3D”

AgendaAgenda

A brief intro to microformatsThe basic concepts

The Good, the bad and the ugly

Bringing Semantic Technology to microformatsSemantic transparency

GRDDL

Leapfrogging microformats altogetherXML or even JSON with Semantic schema

RDF/A

A brief intro to microformatsThe basic concepts

The Good, the bad and the ugly

Bringing Semantic Technology to microformatsSemantic transparency

GRDDL

Leapfrogging microformats altogetherXML or even JSON with Semantic schema

RDF/A

A brief intro to microformatsA brief intro to microformats

In their own words...In their own words...

“Designed for humans first and machines second, microformats are a set of simple, open data formats built upon existing and widely adopted standards. Instead of throwing away what works today, microformats intend to solve simpler problems first by adapting to current behaviors and usage patterns”

—microformats.org

Basic ideaBasic idea

Start with a base schema such as XHTML, or Atom

Define specialized variations

Conventions for use of, say, attribute values already defined by the base schema

Modest set of extensions to the base schema

Start with a base schema such as XHTML, or Atom

Define specialized variations

Conventions for use of, say, attribute values already defined by the base schema

Modest set of extensions to the base schema

Embed minor, specialized variations within established vocabularies

It’s just JargonIt’s just Jargon

Jargon is not inventing a completely new language

Start with an existing language

Come up with variations: specialized syntax or specialized vocabulary (mostly the latter)

Establishing and propagating conventions in the language variation

Formal terms and definitions (professional glossaries)

Informally shared trends

Jargon is not inventing a completely new language

Start with an existing language

Come up with variations: specialized syntax or specialized vocabulary (mostly the latter)

Establishing and propagating conventions in the language variation

Formal terms and definitions (professional glossaries)

Informally shared trends

Elemental microformat examples

Elemental microformat examples

<p>Nice blog. Buy your medz <a href='http://medz.com' rel='nofollow'>here</a></p>

<div class='blogroll'>

<a href="http://chimezie.ogbuji.net/" rel="brother met">Chimezie</a>

</div>

<p>We decided not to implement <a rev="vote-against" href="http://www.w3.org/TR/xquery/" title="way too complex">XQuery</a>...</p>

Compound microformat example

Compound microformat example

<ol class='xoxo'> <li>Subject 1 <ol> <li>subpoint a</li> <li>subpoint b</li> </ol> </li> <li>Subject 2 <ol compact="compact"> <li>subpoint c</li> <li>subpoint d</li> </ol> </li></ol>

XOXO is a microformat for “outline”, which can be anything from “Blogrolls” to presentations

A seriously mixed bagA seriously mixed bag

The good: Rough consensus is good, even for minor syntactic details

The bad: It’s very easy for microformats to clash, because of the lack of Semantic grounding (yes, this is biting people in practice already)

The ugly: Putting it bluntly, have you ever seen an format as horrid as XOXO? That’s what you get when you try to tunnel one set of semantics into another.

(OK granted OPML might be even uglier, but we can create a far more humane format)Note: XOXO was inspired by desire to avoid the horrid macro-format OPML

The Ugly: Absurd markup indirection

The Ugly: Absurd markup indirection

A condition where the attempt to fit a microformat into a host leads to unnaturally indirect markup design

<product> <property> <name>ID</name> <value>xyz123</value> </property></product>

<element tagname='description'> My favorite Weblog</element>

<dl> <dt>description</dt> <dd>My favorite Weblog</dd></dl>

<product xml:id='xyz123'> <name>Widget wonder</name></product>

<description> My favorite Weblog<description>

What to do about the uglyWhat to do about the ugly

Elemental microformats minimize syntactic footprint, and are thus harmless.

Most compound microformats are hopeless cases. In Almost all cases its better to Just Use XML.

Who needs hAtom when Atom does the trick, and is thriving?

XBEL is a more humane alternative to XOXO (and even OPML)

BTW “Ugly” is not a negligible problem. Form is Function.

The bad: Semantic wafflingThe bad: Semantic waffling

Microformats have to in effect steal and re-purpose the host format’s Semantics

Some formats make somewhat dodgy use of host language constructs (e.g. a/@rev in vote-links)

Few microformats have even reasonable syntactic schema, let alone semantic

Microformats have to in effect steal and re-purpose the host format’s Semantics

Some formats make somewhat dodgy use of host language constructs (e.g. a/@rev in vote-links)

Few microformats have even reasonable syntactic schema, let alone semantic

Note: Schematron is a great schema language for the likes of microformats, and even for their semantics. Ask me later about Schematron Abstract Patterns

Microformat profilesMicroformat profiles

Microformat advocates have taken a stab at alleviating the “bad” by specifying a “profile” link from the source document to a description of the microformat.

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml"> <head profile="http://gmpg.org/xfn/11"> <title>Sample document</title> </head>

XMDP for microformat profiles

XMDP for microformat profiles

Microformats descriptions were originally ad-hoc Wiki pages. Profiles movement has defined a super-simple format based on a subset of XHTML.Called XHTML Meta Data Profile (XMDP)

Example Web view of XMDP

What else to do about the badWhat else to do about the bad

XMDP is all about prose description, and is very non-formal

We can do so much better

Bringing Semantic Technology to microformatsBringing Semantic Technology to microformats

Beyond syntaxBeyond syntax

We know that XML is a useful alphabet, but a library of XML needs a reference section for true advancement

That’s what we’re all at this conference to talk about, right?

Microformats need a reference section even more badly, because they often turn simple alphabets into arcane substitution ciphers

Θe quik βroυν φox jυμπσ oveρ θe λειζy δoγ

Semantic transparencySemantic transparency

Semantic transparency is the ability to share context between systems by accessing resources that can be automatically located from the syntax.

Microformats seek to share context, but in their basic form do not offer the tools for context sharing.

Semantic transparency would add value and longevity to documents using microformats.

Just use RDF?Just use RDF?

RDF does provide for semantic transparency, unlike XML, or microformats. It has very formalized semantic expressiveness, and healthy support in tools and standards

We could just advocate standardizing on RDF representations of such rich data.

Let’s get realLet’s get real

RDF/XML’s syntax is awkward, especially for the sorts of prose/narrative documents that serve as host to microformats

N3 and such are better, but hardly likely to inspire enthusiasm with Web authors

RDF is not popular with many in the XML and Web 2.0 world; this “political” battle distracts from getting useful work done

Practical meetingPractical meeting

Time is finally right for a practical meeting of XML and RDF technology I’ve been personally advocating for seven years

Why not use syntax transform technology to extract Semantic details from whatever conventions we can identify in XML and microformats?

Enter GRDDLEnter GRDDL

W3C draft for using transforms such as XSLT to convert XML to RDF

General conventions for associating XML languages with GRDDL transforms

Piggy-backs off microformats profiles

Rather than XMDP the profile link is to a XHTML page with embedded RDF

You would add transforms to the base GRRDL profile for the host language

W3C draft for using transforms such as XSLT to convert XML to RDF

General conventions for associating XML languages with GRDDL transforms

Piggy-backs off microformats profiles

Rather than XMDP the profile link is to a XHTML page with embedded RDF

You would add transforms to the base GRRDL profile for the host language

Pronounced “Griddle”

Short for “Gleaning Resource Descriptions from Dialects of Languages”

Dublin Core/RDF from XHTMLDublin Core/RDF from XHTML

Part of a theoretical script, dc-from-xhtml.xslt, for generating Dublin Core in RDF/XML from XHTML metadata

W3C hosts a very convoluted implementation of this: dc-extract.xsl

...<xsl:template match='xhtml:title'> <dc:title><xsl:apply-templates/></dc:title></xsl:template>...

XHTML GRDDL profileXHTML GRDDL profile

grrdl-example.xhtml

<html xmlns="http://www.w3.org/1999/xhtml"> <head profile="http://www.w3.org/2003/g/data-view"> <title>Some Document</title> <link rel="transformation" href="http://www.w3.org/2000/06/dc-extract/dc-extract.xsl" />

<meta name="DC.Subject" content="ADAM; Simple Search; Index+; prototype" /> ... </head> ...</html>

RDF/XML resultRDF/XML result

<rdf:RDF xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" > <rdf:Description rdf:about=""> <dc:title>Some Document</dc:title> </rdf:Description></rdf:RDF>

Using GRDDL with microformats

Using GRDDL with microformats

grrdl-xfn-example.xhtml

<html xmlns="http://www.w3.org/1999/xhtml"> <head profile="http://www.w3.org/2003/g/data-view"> <title>Some Document</title> <link rel="transformation" href="http://www.w3.org/2000/06/dc-extract/dc-extract.xsl" /> <link rel="transformation" href="http://www.w3.org/2003/12/rdf-in-xhtml-xslts/grokXFN.xsl" /> </head> <body> ... <div class='blogroll'> <a href="http://chimezie.ogbuji.net/" rel="brother met">Chimezie</a> </div> ... </body></html>

GRDDL in practiceGRDDL in practice

The main implementation is a Firefox “GreaseMonkey” script

microcontentextractor.user.js applies GRDDL profiles and builds an aggregated model for the user

GRDDL does provide a way of increasing the formality of microformat models, an important step towards semantic transparency

With GRDDL in place the microformats buzz at least offers Webmasters an rough and ready path toward Semantic technology

The main implementation is a Firefox “GreaseMonkey” script

microcontentextractor.user.js applies GRDDL profiles and builds an aggregated model for the user

GRDDL does provide a way of increasing the formality of microformat models, an important step towards semantic transparency

With GRDDL in place the microformats buzz at least offers Webmasters an rough and ready path toward Semantic technology

Leapfrogging microformats altogetherLeapfrogging microformats altogether

Just use XML (or JSON or...)Just use XML (or JSON or...)

Blogroll example in plain XML (compare XOXO)

Blogroll example in plain JSON

<folder> <title>Technology</title> <weblog href="http://weblog.foo"> <title>Example Weblog</title> <webfeed href="http://weblog.foo/atom" type="application/atom+xml"/> <description>That good ole Weblog</description> </weblog></folder>

[ {"blog": "http://example.com/bud/", "feed": "http://example.com/bud/atom", "description": "My buddy's Weblog", "tags": ["buddy"] } ]

Not as ugly, but just as bad, right?

Not as ugly, but just as bad, right?

Semantic technology advocates need to do a better job of building on plain old XML. GRDDL is a good first step, but more is needed.

This is my primary space of professional interest.

Again: if you see me later, ask me about Schematron Abstract Patterns

As for JSON. Work is just starting, but let’s not forget the XML lesson:

Collaborate rather than compete with emerging syntax.

RDF/ARDF/A

RDF/A is a system for embedding triples right into documents using ideas similar to microformats.

It eliminates the extra transform step required by GRDDL for extracting RDF

Note: RDF/A predates both microformats and GRDDL

rel-license microformat example

rel-license microformat example

rel-license is a microformat for providing a link specifically to the license for the source document.

<html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Some Document</title> </head> <body> ... <p>This document is licensed under a<a rel="license" href="http://creativecommons.org/licenses/by-nc/2.5/"> Creative Commons Non-Commercial License</a>. </p> ... </body></html>

RDF/A license exampleRDF/A license example

In RDF/A you would repurpose an existing RDF vocabulary for a license relationship, and just embed this into the host document

<html xmlns="http://www.w3.org/1999/xhtml" xmlns:cc="http://creativecommons.org/licenses/"> <head> <title>Some Document</title> </head> <body> ... <p>This document is licensed under a<a rel="cc:license" href="http://creativecommons.org/licenses/by-nc/2.5/"> Creative Commons Non-Commercial License</a>. </p> ... </body></html>Yes, QNames in content stink, but they’re all over the XML and RDF worlds

Advantage RDF/A?Advantage RDF/A?

Qualification of the license relationship provides for discovery and semantic precision. The namespace can be treated as a link and dereferenced for discovery and hence Semantic transparency.

That fixes the “bad”, but RDF/A is no help with the “ugly”. Stretching RDF to fit an XHTML skeleton gets grungy in a hurry.

Note: RDF/A is not the same as the Talis “RDF in HTML” system used in the GRDDL profile document. Yeah, we need to get our act together, folks.

Questions?Questions?

ResourcesResources

Microformats Microformats homehome http://microformats.org

““Thinking XML” Thinking XML” columncolumn http://uche.ogbuji.net/tech/publications/thinkingxml

““Perspective on Perspective on XML” columnXML” column http://www.adtmag.com/article.asp?id=8515

GRDDLGRDDL http://www.w3.org/2001/sw/grddl-wg/

““Microformats in Microformats in Context”Context” http://www.xml.com/pub/a/2006/04/26/microformats-grddl-rdfa-

nvdl.html

XMDPXMDP http://gmpg.org/xmdp/

More fun linksMore fun links

http://dannyayers.com/archives/2005/08/01/microformats-on-the-grddl/

http://copia.ogbuji.net/blog/2005-11-16/Does_it_co

...

http://www.oasis-open.org/cover/xmlAndSemantics.html

http://theryanking.com/blog/archives/2005/06/10/wordpress-kubrick-hreview-trouble/