Linked Data: The Real
Web 2.0
Uche Ogbuji <uche@zepheira.com>
17 June 2008, NYC

Warming up...

Hi. I’m Uche Ogbuji
• Partner at Zepheira
•
•
Web architecture & Semantic technology solutions
Ask me about: START, 3D, Remix
• Longtime leader in XML, data integration and
semantic technology
• Lead on key open specs & FLOSS, e.g.
•
•
•
Jacquard Web development methodology
Versa RDF query language
4Suite & Amara XML/RDF tools
Nigerian-American. Father. Husband. Poet. Entrepreneur. Engineer. Tech pundit. Footballer (“soccer”). Snowboarder. Skateboarder. Hip-Hopper.

The goal: enough Linked/Linking (Open) Data
basics for the curious
But enough deep discussion for the initiated

How we got
here

Who wants to repeat Web history?
OK then let’s follow Ken North’s lead and study it...

A brief history...
• The Web, mid-1990s
•
Big daisy chain of home pages. Not much need for context
in hyperlinks.
•
Sloppy was OK. Remember 404s?
• Then it started to get big. Portal wars, search
engine wars, browser wars...
• Sloppy was starting to really hurt...

First wave solutions
• XML for the document weenies. RDF for die
echten menschen
•
Hey, if the W3C builds it, they will come
• Semantic Web FTW!
• Time to sort out the chaos of the Web. Context
by formal declaration.
• Anyone here tried explaining OWL to Joe
Webmaster?

Back to architecture
• Enter SOAP Web services: suddenly we had
more pressing concerns
•
Uh oh! There’s a cuckoo’s egg in the Web
•
Phew! Got that anti-cuckoo detection kit ready just in time
• We fought back with REST
• Lesson learned: if we didn’t keep to the
original, simple principles

What’s that lesson again?
• We think we know what makes the Web work
so well
• We want others to understand, so we want to
have suggestions and tools for them
• We’d better keep to the simplest suggestions
and tools that could possibly serve our cause

Simplest that could possibly...
• So Semantic Web, right?
•
You kidding? Ever tried to explain SemWeb to Joe Webmaster?
•
You kidding? A Ph.D. dissertation? Get Joe Webmaster the Cliff Notes
• So... REST, right?
• OK. OK. I give up...

Spoiler alert!

Tim Berners-Lee breaks
it down for the oh-six

Back to history: Web 2.0
• Bored one day, The Weblog echo chamber
dusted off some old Web tricks
• Enough smart developers came up with
enough simple tools and suggestions to create
a craze
• So is this a catastrophic distraction from what
the Web really needs?

What does Web 2.0
really boil down to?
“Think globally, act locally”

Say what?
• You make some modest enhancements to your site
(the local). That’s all you need to worry about.
• You then roll in the global power of Web-enabled
services: Mashups, feeds, user-generated content...
• ...Mumble...SEO...mumble...long tail...mumble...
• ...Profit
• What Webmastering Joe could resist that call?

But hey!
But wait!
But SWEET!
“Think global, act local” is all we needed from Joe
anyway, right?
You know, to make a better Web????!!!

SCORE!!!!

Web2: Web feeds
• RSS, Atom, JSON...
• For a bunch of non SemWebby guys Atom 1.0
community did a decent job
• Finally gives us a reasonably pervasive format
for reading, with some true context retained
• A small step towards a machine-readable Web
•
Small steps matter!
• Read the Web

Web2: User-generated content
• Hey, isn’t this the write part of the read-write Web
we’ve been craving?
• Thank Wikipedia just for the psychological fillip for
the non-techie: you too can write
•
Sure forums technically offered that for ages, but Wikipedia
carries an clear, broadcast message. It’s prime time.
• Write the Web
• Oh BTW Remember that Web of Trust thingie
SemWebbers were chattering up years ago?
•
Psssssst! We kinda really need that now. Thanks.

Web2: Mashups
• “So, like, all I have to do is focus on the sort of
information I specialize in, and mark it up in
clear context”
• “Yep. And other smart folks just combine it
with other data in ways you never imagined”
• “OK, that’s worth paying some attention to
Web data design”

SCORE!!!!

Web2: Mashups
• Joe’s sophistication might end with mashing, but a
good data architect can make meshes of mashes
• Remix and Re-purpose the Web

Sure, sure, but all that is why we’re Web 3.0
We’re too cool for small steps!

Yeah, because version number wars did so much
good for...
Office suites
DBMS
RSS

We’re not different from
Web 2.0
We’re just Web 2.0, properly
• Vendor independent
• Scalable
• Extensible
• Multi-device friendly.
•
It’s not just about the PC/Mac bowser, you know

Marketing command: What would Web 2 do?
Heresy maybe, but marketing matters, even when
you’re just trying to do the right thing

Give them something they can figure out in 10
minutes

Linked Data

Linked Data means just
remembering 4 things
1. Use URIs as names for things
2. Use HTTP URIs so that people can look up
those names.
3. When someone looks up a URI, provide useful
information.
4. Include links to other URIs. so that they can
discover more things.

From kernels of wisdom
grow...
• Joe Webmaster can understand this, and
probably remember this
• #3 and #4 are openings for clever types to
push for more
•It’s all about the link, ya’ll

<a href...
• The granddaddy link
• The most pervasive link
• Limited for preserving context
•
@rel, @type and such do help
• Just plain Limited.

XLink? Hlink?
• OK <a href is limited, but at least you can
grasp it in minutes
• We like our snoozefest flame wars, eh?
•
How many URI hashes/slashes can dance on the head of a
pin?
•
What is the link to the divine? Sophisticated Gnosis?
Simpleton Chrestos? The 3-personed markup?
• Needless to say, not too many people are
using XLink, HLink and friends

RDF
• RDF is in effect a linking technology
•
<a xml:base=”Subject” href=”Object” rel=”predicate”>...
• Generally separate from described resources
(not unlike XLink link-bases)
• Also a fairly heavy conceptual burden
• An unfortunate syntax is more prevalent than
the useful model

That will bring us back to...

Yes: <a href...
• Worse is better, folks
• Just a few careful conventions and we can
squeeze a bit more out of it
•
•
@rel conventions
@type coordinated with core HTTP (media types, content
negotiation, etc.)
• Let’s first see what we can build on that, then
worry about the gaps

Linking Open
Data

Clever types building on
Linked Data
• Emphasize a particular set of conventions and
tools for refining Linked Data
•
HTTP usage such as content negotiation or 303s for linking
to abstract resources
•
Syntax layer usage such as RDFa and GRDDL
• Emphasize a particular set of sites as seeds for
growing Linked Data
•
DBPedia is the star

RIchard’s LOD bubble
diagram

What would Web 2 do?

Kingsley’s four techniques
1. Handle Content Negotiation requests
2. <link rel=-"alternate"..../> (when HTML is
requested)
3. GRDDL profile in <head/> plus <link
rel="transformation".../> (when (X)HTML or
XML is requested)
4. eRDF or RDFa (when HTML or (X)HTML is
requested)
Note: Taken from a community posting. See Kingsley’s
presentation for his own refinement of this...

This is exciting. We’re hitting our stride folks.

Just one thing: Don’t forget the nuanced message
for Joe CIOverlord

Linking
Enterprise
Data

What is LED?
• A community project to develop tools and
architectural strategies to bring Sensible SOA to
the Enterprise through data-driven applications
• You’ve heard of Linking Open Data?
LED comes in
when the data can’t always be so open
• You’ve heard of Enterprise 2.0 and Enterprise
Mashups? LED comes in when you need such
applications to outgrow the toy box
•
Same relationship as with Linked Data to Web 2.0

Business context
• LED involves using tools to express business
context as rich, reusable metadata (often RDF)
• LED involves using well-known data
syndications tools to orchestrate data
enriched with this context
• LED involves using formally expressed policy
to control data flow and capture responsibility

Bridge to legacy
• Rather than the ERP-type play to replace
legacy apps with a centralized super-model,
LED focuses on wrapping and exposing data in
those apps
• The exposed and contextualized data from
source applications is integrated using basic
Web technology

LED step by step
• Capture business context during analysis
• Capture business rules and policy during
analysis
• Express these in simple, sharable, reusable
formats made available to people as well as
code (SKOS, Attempto-Controlled English,
etc.)
• Map data models of existing applications to the
expressed context (declarative data transform)

More LED step by step
• Architect Web integration layer around
documented context
• Use mappings to drive Web-feeds from legacy
apps to the integration layer (JSON, Atom,
RDF, etc)
• Use lightweight so-called Web 2.0 kit to
simplify browser access

Questions?
uche@zepheira.com
http://zepheira.com