Semantics to the Bookmarks:
A Review of Social Semantic
Bookmarking
Systems
Simone Braun,
Claudiu Schora,
Valentin Zacharias

This Presentation
• Goal: An overview of the state of the art in Social
Semantic Bookmarking
• Part 1: Introducing Social Semantic Bookmarking
• Part 2: Social Semantic Bookmarking Systems
• Part 3: Some Important Differentiating Dimensions

Part 1:
Introducing Social
Semantic Bookmarking
• Part 1.1:
Social Bookmarking Systems
• Part 1.2:
Semantic Annotation Systems
• Part 1.3:
Social Semantic Bookmarking

Social Bookmarking, Definition
• Bookmark:
Manually created reference to (internet)
content deemed interesting
• (Linguistic) Tag:
Arbitrary keyword assigned to an entity
(e.g. bookmark) to aid in management and
retrieval
• Social Bookmarking Site:
Website facilitating discovery of interesting
content & persons through shared tags and
bookmarks

Social Bookmarking – Advantages &
Disadvantages
• Advantages:
Lightweight, easy to use, adaptable,
no setup, proven – used by millions of
users.
• Disadvantages:
– Lack of precision due to (Mis-)Spelling,
Polysemy, Homonymy
– Lack of recall due to Multilingualism,
Synonymy, Basic Level Phenomena

Semantic Annotation, Definition
• Annotation:
An addition made to an entity to aid
management, retrieval etc.
• Semantic Annotation:
OntoMat
An annotation done using a term
described with some background
knowledge
– (usually contained in an ontology)
– e.g. its relation to other terms

Semantic Annotation – Advantages &
Disadvantages
• Advantages:
– Better Retrieval due to explicitly represented
concept relations
 improving query and browse functionality
– Better Use Of Annotation due to standardized
languages and machine understandable
annotations
 allow for better interoperability between systems

Semantic Annotation – Advantages &
Disadvantages
• Disadvantages:
– High Cost: Ontologies are usually created by highly
paid knowledge engineers that also first need to
learn about the domain
– Low Appropriateness due to the technical,
personal and temporal separation between
creation and use of ontology
heavyweight process
large upfront investment
high time lack between concept emergence and
inclusion in ontology
errors due to limited domain understanding of
knowledge engineers

Social Bookmarking vs.
Semantic Annotation
• Social Bookmarking lacks semantic
precision and recall
• Semantic Annotation stumbles
because of the separation between
creation and use of the semantic
model
• Social Semantic Bookmarking
combines the advantages of both
while avoiding the problems

Social Semantic Bookmarking
Combines these paradigms
• by allowing lightweight and social
organization of bookmarks
• with tags extended by semantic
definitions and descriptions
• that also evolve (collaboratively) within
the same system

Part 2:
Social Semantic
Bookmarking Systems
• BibSonomy • ZigTag
• SOBOLEO • Faviki
• Fuzzzy • gnizr
• GroupMe • Annotea
• Twine

BibSonomy
• System for the management of
internet resources and publication
entries, tailored towards academics
• Created by the University Kassel
• Extends the tag model with relations
between tags
Try it at:
http://www.bibsonomy.org/
No Installation

SOBOLEO
• SOBOLEO: SOcial BOokmarking and
Lightweight Engineering of Ontologies
• Social Semantic Bookmarking System
created by FZI
• Allows simple tags but also concepts
with multiple labels, relations etc.
• Supports a community of practice in the
joint structuring of Try it at:
a domain. http://tool.soboleo.com/
No Registration, No Installation

Fuzzzy
• Manages bookmarks of internet
resources, ISBN numbers, media files
and geographic locations
• Developed at the University of Oslo
• Allows a large number of relations
between tags
• Unique in that it allows voting on all
aspects of the semantic model to
facilitate gardening Try it at:
http://www.fuzzzy.com
No Installation

GroupMe!
• Bookmarking of web resources with ‘tag
groups’ as additional structure
• Created by the University of Hannover
• Additional focus on making bookmarks
of multimedia resources more easily
accessible
Try it at:
http://groupme.org/
No Installation

Twine
• Organizing and sharing of bookmarks of
web pages, images, videos, products and
books
• Commercial product developed by Radar
Networks
• Main ordering principle “Twine” – kind
of user interest group. Tags related
through use in same Twine
• Extensive use of automatic classification
to reduce tagging effort Try it at:
http://www.twine.com
No Installation

ZigTag
• Organizes bookmarks of internet
resources
• Commercially run by a small
Canadian company
• Allows the users to choose from a
given list of tags (‘ZigTags’) with a
specific meaning
• Sets ‘ZigTags’ automatically into
Try it at: relation
http://www.zigtag.com
No Installation

Faviki
• Manages bookmarks of internet
resources
• Developed by Serbian Web
designer Vuc Milicic
• Unique in that it relies on
Wikipedia articles as tags
• Uses DBpedia to support
multilinguality Try it at:
http://www.faviki.com
No Installation

Part 3:
(Some) Important
Differentiating Dimensions
• Part 3.1: Tag Relations
• Part 3.2: Semantic Consistency
• Part 3.3: Use of Semantics
• Part 3.4: Export & Interoperability

Tag Relations
• All analyzed systems provide support
for relations between tags
• Only SOBOLEO, Fuzzzy and BibSonomy
allow explicitly user created relations
• For Twine and GroupMe! tag relations
are indirectly affected by users
creating collections

Semantic Consistency
• Structure is local, i.e. only usable by
the user that created it (BibSonomy)
• Global structure is maintained
collectively according to Wiki
principle (SOBOLEO, Fuzzzy)
• Global structure is only indirectly
computed from user actions
(GroupMe!, Twine)
• Global structure is imported or only
edited by administrators (ZigTag,
Faviki)

Use of Semantics
• Additional semantics is mainly used
to support tag-based navigation
• As far as we know, no inferencing
engine is used
• Integrating semantics into keyword
based search is an area of current
active development (e.g. Faviki,
SOBOLEO, Twine)

Export & Interoperability
• Data Exchange and Interoperability main
promise of Semantic (Web) Technologies
• All systems support some kind of export
functionality, but varied and incompatible
formats (BURST, SWRC, XTM, DCMI, SKOS,
SCOT ..)
• Promise of interoperability currently not
realized, but active area with CommonTag as
format that could make interoperability
possible

Summary
• Social Semantic Bookmarking Systems
combine Social Bookmarking and Semantic
Annotation
– by allowing lightweight, flexible annotation
– but also more complex and formal description of
tags
– wich evolve (collaboratively) within the same
system

Summary
• At least seven such systems are actively
developed: BibSonomy, SOBOLEO, Fuzzzy,
GroupMe!, Twine, ZigTag and Faviki
• Import differentiating dimension and areas of
current development are:
– kind of relations
– edit scopes
– the use of the semantics
– export formats

Thank you for your
Attention !
• Simone Braun
(braun@fzi.de)
• Claudiu Schora
(Claudiu.Schora@fzi.de)
• Valentin Zacharias (zach@fzi.de)
SOBOLEO demo at 3:40 pm at
MATURE project booth or
try SOBOLEO at:
http://tool.soboleo.com/
No Registration, No Installation