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Semantic Web. Social Semantic Web. Where are we?. Agenda. Motivation From Web to Web 2.0: Technical solution and illustrations Social Semantic Web : Technical solution and illustrations Summary References. MOTIVATION. Motivation. 5. Motivation (cont‘d). Information Sharing:

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Semantic Web

Social Semantic Web

Where are we?


  • Motivation

  • From Web to Web 2.0: Technical solution and illustrations

  • Social Semantic Web : Technical solution and illustrations

  • Summary

  • References




Motivation (cont‘d)

  • Information Sharing:

    • Image sharing: Flickr

    • Video sharing: YouTube

    • Online encyclopedia: Wikipedia

    • Blogs: eblogger

    • Open Source Community: Linux

  • File Management

    • Tagging: Delicious

  • Social Websites and Communication:

    • Facebook

    • LastFM

    • Skype

    • StudiVZ

    • LinkedIn, Xing

  • Open Systems: APIs, partly open source allow extensions by users

Motivation (cont‘d)

Internet platform for creation of social networks

  • More than 400 million active users

  • 50% of our active users log on to Facebook in any given day

  • More than 35 million users update their status each day

  • More than 60 million status updates posted each day

  • More than 3 billion photos uploaded to the site each month

  • More than 5 billion pieces of content (web links, news stories, blog posts, notes, photo albums, etc.) shared each week

  • More than 3.5 million events created each month

  • More than 3 million active Pages on Facebook

  • More than 1.5 million local businesses have active Pages on Facebook, 17.2.2010

Motivation (cont‘d)


Free Online Encyclopedia

  • 3,197,507 Articles (english Wikipedia)‏

  • 11,693,499 registered contributors

  • Clever mechanisms combined with human intelligence

  • High quality articles

  • Self-organized control

  • Semi-openess, 17.2.2010


Web 1.0 to Web 2.0

  • Evolution

  • Definition

  • Applications and success stories

  • Statistics to Web 2.0

Web 2.0

“Web 2.0 is a notion for a row of interactive and collaborative systems of the internet“

What is the web 2.0? „Definition“ by O‘Reilly

Web 1.0Web 2.0improvement

DoubleClickGoogle AdSensepersonalized

OfotoFlickrtagging, community

Britannica OnlineWikipediacommunity, free content



CMSwikisflexibility, freedom

directories tagging community


Consumers  Prosumers

What is the Web 2.0? - Examples

  • Gmail

  • Google Documents (Collaborative Notepad in the Web)

  • Wikis

  • Wikipedia

    • Worlds biggest encyclopedia, Top 30 web site, 100 langueges

  • (Social Tagging for Bookmarks)

  • Flickr (Photo Sharing and Tagging)

  • Blogs, RSS,

  • (APIs)


  • Easy usable user interfaces to update contents

  • Easy organization of contents

  • Easy usage of contents

  • Easy publishing of comments

  • Social: collaborative (single users but strongly connected)‏



  • Wiki  invented by Ward Cunningham

  • Collection of HTML sites: read and edit

  • Most famous and biggest Wiki: Wikipedia (MediaWiki)

    • But: Also often used in Intranets (i. e. our group)

  • Problems solved socially instead of technically

  • Flexible structure

  • Background algorithms + human intelligence

  • No new technologies

  • social: collaborative (nobody owns contents)‏

Wikis: Design Principles

  • Open

    Should a page be found to be incomplete or poorly organized, any reader can edit it as they see fit.

  • Incremental

    Pages can cite other pages, including pages that have not been written yet.

  • Organic

    The structure and text content of the site are open to editing and evolution.

  • Mundane

    A small number of (irregular) text conventions will provide access to the most useful page markup.

  • Universal

    The mechanisms of editing and organizing are the same as those of writing so that any writer is automatically an editor and organizer.

  • Overt

    The formatted (and printed) output will suggest the input required to reproduce it.



  • Idea: Enrich contents by user chosen keywords

  • Replace folder based structure by a organisation using tags

  • New: Simple user interfaces for tagging and tag based search

  • First steps to Semantic Web?

  • Technically: user interfaces

  • Social: collaborative (own contents, shared tags)


Collaborative Tagging

Collaborative Tagging: Delicious

  • Browser plug-ins available from

  • Allows the tagging of bookmarks

  • Community aspect:

    • Suggestion of tags that were used by other users

    • Availability of tag clouds for bookmarks of the whole community

    • Possibility to browse related bookmarks based on tags















Data created by tagging, knowledge structures

Mary tags with wiki wikipedia encyclopedia

Bob tags with wiki web2.0 encyclopedia knowledge

Folksonomies: Taxonomie Marlow et al. (2006)

  • Rights for Tagging

    • Self-tagging: Contents only tagged by owner (Technorati)

    • Free-for-all tagging: Tagging by all users (Yahoo!)

  • Support of Tagging

    • Blind Tagging: Existing Tags are not displayed (Flickr)

    • Viewable Tagging: Existing Tags are displayed (

    • Suggestive Tagging: Suggestions for Tags (MyWeb 2.0)

  • Aggregation of Tags

    • Bag-model: Multiple entries (

    • Set-model: Only single entries (YouTube)

Tag Clouds

Size of Tags: count of usage

Browsing replaces Searching

Different meaning for different users

Orientation in Information Set

What is the Web 2.0? Trends for Web Applications

  • Technical Evolution

    • Web User Interfaces become faster (AJAX)

    • Desktop shifts to Web (GMail, Google Notebooks, AJAX)

  • Social Evolution

    • Collective creates additional value (Wiki, Tagging)

    • Free contents become popular (Licenses)

    • Attention is getting monetarized (Text-Ads)

    • Websites with additional value by recombination (Mash-Ups, RSS)

Web 2.0

People, Services, Technologies

Web 2.0

  • Web 2.0 is a vaguely defined phrase referring to various topics such as social networking sites, wikis, communication tools, and folksonomies.

  • Tim O'Reilly provided a definition of Web 2.0 in 2006: "Web 2.0 is the business revolution in the computer industry caused by the move to the internet as platform, and an attempt to understand the rules for success on that new platform. Chief among those rules is this: Build applications that harness network effects to get better the more people use them."

  • Tim BL is right that all these ideas are already underlying his original web ideas, however, …

Web 2.0

The four major breakthroughs of Web 2.0 are:

  • Blurring the distinction between content consumers and content providers.

  • Moving from media for individuals towards media for communities.

  • Blurring the distinction between service consumers and service providers.

  • Integrating human and machine computing in a new way.

Blurring the distinction between content consumers and providers

Interactive Web applications through asynchronous JavaScript and XML (AJAX)

Blurring the distinction between content consumers and providers

Interactive Web applications through asynchronous JavaScript and XML (AJAX)

Blurring the distinction between content consumers and providers:

Weblogs or Blogs, Wikis

Blurring the distinction between content consumers and providers:

Flickr, YouTube

Blurring the distinction between content consumers and providers

Tagging –,

Blurring the distinction between content consumers and providers

RDFA, micro formats

Moving from a media for individuals towards a media for communities

Folksomonies, FOAF

Moving from a media for individuals towards a media for communities

Community pages (friend-of-a-friend, flickr, LinkedIn, myspace, …)

Moving from a media for individuals towards a media for communities

Second Life

Moving from a media for individuals towards a media for communities


Moving from a media for individuals towards a media for communities


Blurring the distinction between service consumers and service providers

RSS feeds

Blurring the distinction between service consumers and service providers

Yahoo pipes allow people to connect internet data sources, process them, and redirect the output.

Blurring the distinction between service consumers and service providers

Widgets, gadgets, and mashups.

Integrating human and machine computing in a new way

Amazon Mechanical turk

Integrating human and machine computing in a new way

Human computing (captchas)


Web 2.0

Web 3.0


  • Annotation with Tags

  • Singular/Plural Problem

  • Synonyms

  • No Intelligence

  • Annotation with concepts

  • Inference (Tag „Dog“ --> Tag „Pet“)

Recombination of data from different sources

  • Mash-Ups developed earlier by programmer

  • Spontaneous by End User


  • Keyword Search or Tag Search finds documents

  • Structured Search combines Data und creates documents


  • 2004 - 2007

  • 2007 – 2010

Semantic Web + Web 2.0 = Web 3.0?

Based on Völkl, Vrandecic

and colleagues.


Web 3.0 Approaches

  • Automatic Extraction of knowledge based on large (and free) sets of data, generated by Web 2.0

  • Integration and Reuse of knowledge (Yahoo Pipes)

  • Motivate users for generating semantic contents by using Web 2.0 paradigms

  • Creation of Semantic as side effect of working processes (semantic wikis)

Gartner Hype Curve

Gartner, July 2007

Web 2.0 and the Semantic Web

  • Web 2.0 and Semantic Web are complementary approaches

  • Semantic Blogging

  • Semantic Wikis

    • Semantic MediaWiki

  • Web 2.0 ontology building

    • myOntology

  • Games for semantic content creation

    • OntoGame

Semantic Blogging

  • Creating blog entries in a structured fashion

  • Based on ontologies

  • This allows:

    • Acquiring complementary information from the Web

    • Finding blog entries better

Semantic Wikis

  • A semantic wiki is a wiki that has an underlying model of the knowledge described in its pages.

  • Regular, or syntactic, wikis have structured text and untyped hyperlinks.

  • Semantic wikis, on the other hand, allow the ability to capture or identify information about the data within pages, and the relationships between pages, in ways that can be queried or exported like database data.

  • Wikis:

    • Platypus wiki

    • IkeWiki

    • Kiwi

    • WikiFactory

    • Semantic MediaWiki

Semantic Wikipedia: Advantages

Structured Knowledge can be exported (in RDF)

  • New Web 2.0 Applications are possible

  • Reusing of knowledge beyond languege borders

  • Aggregated Search over more than one site

  • Quality: Finding of mistakes and conflicts

    • Has every country a capital city?

    • Is every person born before dying?

    • Does the population density match to population and area?

Based on Völkl, Vrandecic

and colleagues.

Semantic Wiki = Wiki + Semantic Web

  • Semantic MediaWiki: Extension of the MediaWiki Software

  • Syntax extension allows typed links

  • Page Karlsruhe

    • Up to now: … in the south of [[Germany]] …

    • Now: … in the south of [[is in::Germany]] …

  • Syntax extension allows annotaion of values

  • Page Karlsruhe

    • Up to now: … has a population of 280,000 people. …

    • Now: … has a population of [[population:=280000]] people.

Based on Völkl, Vrandecic

and colleagues.

Semantic MediaWiki

Based on Völkl, Vrandecic

and colleagues.

What is located in California?

Based on Völkl, Vrandecic

and colleagues.

Web 2.0 ontology building

  • Make use of various Web 2.0 paradigms to capture knowledge required for ontologies

  • Lower entrance barriers for users

  • Usually emphasis on collaboration

  • Ontologies as community contracts

  • Methods for consensus finding

  • Visualization of ontologies

  • Examples:

    • Ontology editor based on SMW

    • Myontology

    • Soboleo (image annotation)

Ontology editor for Semantic MediaWiki


Semantic Media Wiki – Ontology Editor

Ontology Element Management

Management of vocabularies, categories, properties, and elements

Enhanced user interface: tagcloud, forms, tree-view

Enriched content through external media (e.g. Flickr)‏

Knowledge Repair

Statistical analysis of knowledge within the wiki

Detection and correction of inconsistencies

Discovery of redundancies

Knowledge Import

Folksonomy import through mapping to the SKOS ontology

The create functionalities-category

  • Primary navigation

    • Create functionalities

    • Import functionalities

    • Knowledge repair

    • Media Wiki links

  • Introduction

  • Important links

  • Content overview

  • Tag Cloud

The create functionalities-category

  • Input form

    • Name

    • Description

  • Auto completion

  • Entity creation

  • Automatic annotations

  • Overview page

The create functionalities-category

  • Introduction

  • Input fields

    • Name

    • Vocabulary

    • SeeAlso

    • Synonym

    • Example

    • Description

  • Properties

    • New ones

    • Existing ones

  • Supercategories

  • Name analysis

  • Help fields

Knowledge repair-cycles, links, names

  • Comprehensive overview

  • Table with explanations

  • Table with min, avg, max values

  • Table with results for each category

  • Colored cells and symbols to indicate probable issues

Knowledge repair-cycles, links, names

  • Tab ´repair´

  • Repair of a specific category

  • Explanations

  • Tables with numerical values

  • Paragraphs and lists

Knowledge repair-cycles, links, names


  • Collaborative creation of ontologies

  • A tool which helps specialists and ontology experts to collaborate easily

  • MyOntology uses the Web 2.0 paradigm


myOntology Philosophy

  • Collaboration of specialists and ontology experts

  • In first phase (until lightweight ontologies)

  • High usability

  • Integration and Reusing of web knowledge (Web 2.0: Folksonomies, Flickr, YouTube, Wikipedia, etc.)‏

  • „Background intelligence“ supports development team

Games for semantic content creation

A prerequisite for the Semantic Web to become a reality is the availability of annotated data.

Building the Semantic Web is not a one-time task, but a continuous effort.


There are tasks that are easy for humans but difficult for computers

Cf. Von Ahn

Not all the tasks on the Semantic Web can be automated.

Some at least partly require human intelligence.

Web 2.0 is Hot, Semantic Web is Not. Why?

  • Web 2.0 applications enjoy great popularity

  • The incentive structures are clear (Marlow et al.,2006; Kuznetsov, 2004)

  • Incentives for ontology building, ontology alignment, and semantic annotation have not been investigated so far

The OntoGame Idea and Principles

Make people weave the Semantic Web by playing cool multi-player online games.

  • Fun and intellectual challenge

  • Consensus

  • Massive content generation

10 Challenges

  • Identifying suitable tasks in semantic content creation

  • Designing games

  • Designing a usable, attractive interface

  • Identifying suitable knowledge corpora

  • Preventing cheating

  • Defusing typical pitfalls of conceptual modeling

  • Distribution of labor

  • Fostering user participation

  • Deriving formal representations

  • Scalability and performance

TheOntoGame Series


  • Players paired randomly and anonymously

  • Best strategy to get points: truthful answers

  • Live mode, single player mode, chess mode (remote)

  • Skip

  • Limited amount of time

  • Cheating:

    • Anonymity

    • Pre-recorded challenges

  • Generic gaming platform

  • Derive formal representations of the data

OntoPronto:Creating a Huge Domain Ontology

OntoTube: Annotating YouTube videos



  • The Web has undergone change from „Web 1.0“ to „Web 2.0“.

  • Web 2.0 stands for more user interaction, the change from consumers to prosumers, the programmable Web, collaboration, easy interfaces, etc.

  • This movement has triggered enormous user participation. Many tools provide strong incentives to their users.

  • Social Semantic Web approaches aim at combining parts of Web 2.0 with semantics.

  • Examples including Semantic Wikis, Semantic blogs, games for Semantic content creation, etc.



  • Mandatory reading:



  • Further reading:


    • S. Braun, A. Schmidt, A.Walter, G. Nagypal, and V. Zacharias. Ontology maturing: A collaborative web 2.0 approach to ontology engineering, May 8 2007.

    • S. E. Campanini, P. Castagna, and R. Tazzoli. Platypus wiki: a semantic wiki wiki web. pages 16, December 10 2004.

    • Peter Mika. Ontologies are us: A unied model of social networks and semantics. volume LNCS 3729. Springer, 2005.

    • S. Schaffert. Ikewiki: A semantic wiki for collaborative knowledge management. June 2006.

    • K. Siorpaes, M. Hepp, A. Klotz, and M. Hackl. myontology: Tapping the wisdom of crowds for building ontologies. Technical report, STI Innsbruck Technical Report, 2008.

    • K. Siorpaes and M. Hepp. Games with a purpose for the semantic web. IEEE Intelligent Systems, 23(3):5060, 2008.

    • M. Völkel, M. Krötzsch, Denny Vrandecic, and H. Haller. Semantic wikipedia. May 23-26, 2006.


  • Wikipedia links:



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