Folksonomies as Subject Access - A Survey of Tagging in Library Online
Catalogs and Discovery Layers
Yan Yi Lee & Sharon Q. Yang
Abstract
This paper describes a survey on how system vendors and libraries handled tagging in OPACs
and discovery layers. Tags are user added subject metadata, also called folksonomies. This
survey also investigated user behavior when they face the possibility to tag. The findings indicate
that legacy/classic systems have no tagging capability. About 47% of the discovery tools provide
tagging function. About 49% of the libraries that have a system with tagging capability have
turned the tagging function on in their OPACs and discovery tools. Only 40% of the libraries that
turned tagging on actually utilized user added subject metadata as access point to collections.
Academic library users are less active in tagging than public library users.
Introduction
Folksonomy is “a term created by Thomas Vander Wal by combining taxonomy with folk”
(Steele, 2009). Simply put, folksonomy is a classification of resources created by the general
public. Users add keywords to describe a resource on the Web and those user generated
keywords are called tags. The action of adding tags is called tagging. Tag cloud refers to the
display of the accumulated tags as a way to access resources. Gene Smith describes a tag cloud
as "a method of presenting tags where the more frequently used tags are, emphasized usually in
size or color. Tag clouds tell you at a glance which tags are more popular. Each tag is a link"
(Smith, 2009). Tag cloud is a visual subject classification scheme showing more popular or less
important resources based on the font and color of terms. See Figure 1 for example of a tag cloud.
Figure 1. Tag Cloud in the OPAC of Stow-Munroe Falls Public Library
1
Both librarians and computer scientists became interested in tagging and tag cloud from their
inception. In the last five years there were many studies to compare user-created tags with
controlled vocabularies, especially the Library of Congress Subject Headings (LCSH). In 2007,
Tiffany Smith compared the LC subject headings in five books to tags for the same books found
in LibraryThing. Even though he set out to measure the efficacy of tagging as subject access, he
did not reach any concrete conclusions. Since then there have been many studies on a larger
scale to compare LCSH with tags in LibraryThing. Those include the studies by Heymann and
Garcia-Molina (2009), Lawson (2009), Peterson (2009), Rolla (2009), Wetterstrom (2009),
Thomas (2009), Liu, Park, and Hu (2010), just to name a few. Methodology of most research in
this area included extracting titles, ISBNs, and LC Subject Headings in MARC 650 fields of
OCLC or LC bibliographic records and searching the same books in LibraryThing by ISBN. The
LCSH and tags for the same books were compared for duplication, quality, coverage, and
effectiveness.
Thus far all the research, either by librarians or computer scientists, has been positive about
tagging. Findings indicate that folksonomies often use different terms from LCSH and can
provide additional subject access to library collections although sometimes there may be up to 60%
overlapping (Yi and Chan, 2009). User generated tags may cover more aspects of a book’s
subject (Rolla, 2009). Linking folksonomies to LCSH has been called for by Yi and Chan (2009).
Even the Library of Congress Working Group on the Future of Bibliographic Control “has
suggested that libraries should open up their catalogs to allow users to add descriptive tags to the
bibliographic data in catalog records” (Rolla, 2009).
It has been almost a year since the last study yielding positive findings about tagging as a viable
subject access point to compliment LCSH and other controlled vocabularies in online catalogs.
What actions have vendors taken to incorporate tagging into library systems? What have libraries
done to add folksonomies in addition to LCSH in bib records? How do users respond to tagging
capability in library catalogs and discovery tools? This paper aims to answer those questions by
conducting a survey of library systems, libraries, and tagging activities by users.
Library Systems and Folksonomies
Have system vendors taken folksonomies into consideration when designing catalogs and
discovery tools? In order to find out how the current library systems handle folksonomies, the
authors used Marshall Breeding’s Technology Guide (Breeding, 2012) to obtain a
comprehensive list of major library systems with an OPAC, including 37 Integrated Library
Systems (ILS) and 15 discovery tools (also referred to as next generation catalog). An extensive
study of all the 37 major ILS systems revealed that only two ILS OPACs, Koha and Genesis G3,
allow users to add tags and only Koha uses tags to enhance subject access. See Figure 2 for a list
of the ILS.
2
Figure 2. ILS OPACs
Library Automation
System
Allow Users to
add tags
Tag
Cloud
Tag
List
Tag to start a
new search
Tag to refine
a search
Column1
1
Agent VERSO
No
No
No
No
No
2
Aleph 500
No
No
No
No
No
3
Alexandria
No
No
No
No
No
4
Amlib
No
No
No
No
No
5
Apollo
No
No
No
No
No
6
Athena
No
No
No
No
No
7
Atriuum
No
No
No
No
No
8
Carl.X
No
No
No
No
No
9
Circulation Plus
No
No
No
No
No
10
Concourse
No
No
No
No
No
11
DB/TextWorks
No
No
No
No
No
12
Destiny
No
No
No
No
No
13
Dynix
No
No
No
No
No
14
EOS Web
No
No
No
No
No
15
Evergreen
No
No
No
No
No
16
Evolve
No
No
No
No
No
17
Genesis G3
Yes
No
No
No
No
18
GLAS
No
No
No
No
No
19
Horizon
No
No
No
No
No
20
InfoCentre
No
No
No
No
No
21
22
Innopac
Koha
No
Yes
No
Yes
No
No
No
No
No
No
23
Liberty3
No
No
No
No
No
24
Library Solution
No
No
No
No
No
25
LibraryWorld
No
No
No
No
No
26
Mandarin M3
No
No
No
No
No
27
Millennium
No
No
No
No
No
28
OPALS
No
No
No
No
No
29
Polaris
No
No
No
No
No
30
Portfolio
No
No
No
No
No
31
ResourceMate
No
No
No
No
No
32
Spydus
No
No
No
No
No
33
Unicorn (Symphony)
No
No
No
No
No
34
Virtua
No
No
No
No
No
35
Voyager
No
No
No
No
No
36
Vubis Smart
No
No
No
No
No
37
Winnebago Spectrum
No
No
No
No
No
Total
5.41%
2.70%
0.00%
2.70%
0.00%
3
Only about 5% of the major library systems allow tagging. It comes as no surprise that most
legacy or classic ILS do not embed folksonomies as they were developed in the 1990s when
folksonomy was not yet popular. User contributed tags and tag lists or clouds more often exist in
the newer ILS such as Koha, which was created in 1999, (Koha Library Software Community,
2012) and discovery tools that have come into existence in the past five years.
A discovery tool is a stand-alone catalog with advanced features of next generation catalog
(NGC) that is developed independently from any ILS. Libraries can use a discovery tool to
replace its OPAC or use it side by side with the OPAC. The following is a list of 15 major
discovery tools that have been deployed worldwide. Authors randomly chose ten examples from
user lists for each discovery layer compiled by Marshall Breeding (Breeding, 2012) and
examined presence and absence of folksonomies and how they are being used as subject access
in the chosen implementations. Observing a system in action will shed light on its design. The
documentation for a system is consulted for clarification when necessary. The findings are
summarized in Figure 3.
Systems
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
AquaBrowser
AXIELL ARENA
Blacklight
Biblio Commons
EBSCO Discover Service
Encore
Endeca
Enterprise
Primo
Scriblio
Summon
SOPAC
Visualizer
VuFind
WorldCat Local
Total
Figure 3. Folksonomies within Discovery Tools
Allow Users
Tag Cloud
Tag list
to add tags
Yes
No
No
Yes
No
Yes
No
No
Yes
No
No
Yes
No
Yes
Yes
47%
Yes
No
No
No
No
Yes
No
No
Yes
No
No
Yes
No
No
Yes
33%
Yes
No
No
Yes
No
Yes
No
No
Yes
No
No
No
No
Yes
Yes
40%
Tag to start a
new search
Yes
No
No
Yes
No
Yes
No
No
Yes
No
No
Yes
No
Yes
Yes
47%
Tag to
refine a
search
Yes
No
No
Yes
No
Yes
No
No
No
No
No
No
No
No
No
20%
Only 7 out of 15 discovery tools (about 47%) provide tagging function. Only one third of the
discovery tools are capable of displaying tags as a cloud with visual representation by fonts and
size based on frequency of use and popularity. About 40% can display a tag list which looks like
clickable Library of Congress subject headings. About 47% of the discovery tools use tags to
execute a new search, while only 20% use it to refine or narrow a search. A system that allows
users to add tags may not necessarily provide tag cloud or list as subject access.
Encore, Biblio Commons, and AquaBrowser are the best in tagging among discovery tools.
Encore can choose to display either a tag cloud or a tag list to refine or narrow a search. Its tag
4
cloud or list is a mixture of user added tags and keywords from bibliographic records. Drawing
keywords from bibliographic records will make sure that the tag cloud is always present with an
abundance of tags. The user added tags are also displayed separately under “Community Tags”
in a record view and will execute a new search to retrieve all the items being tagged.
AquaBrowser displays “a word cloud” for variant spelling, related words/associations, and
synonyms and its tag cloud is not based on user added tags. In AquaBrowser the real tag cloud
contributed by a user remains private in a user’s account behind login. Biblio Commons displays
tags at the start page for searching and later as a facet to refine or narrow a search. All three of
the discovery tools are doing an excellent job with folksonomies as additional subject access to
collections.
Libraries and Folksonomies
When an ILS OPAC or discovery tool has tagging capability, did libraries take advantage of this
function? The authors chose Koha OPAC as an example and did a survey of tagging activities in
the OPACs of 307 Koha implementers.
Koha is an open source ILS that is widely used in libraries all over the world. Tagging is one of
the important features in its system design. After adding tags, users can choose to keep these tags
private and hidden in his account, or publish them in OPAC as a “Cloud”. Subsequently
librarians can decide to turn on or off a “Tag Cloud”. Librarians also decide whether the tags
created by users can be published in OPAC directly, or must be proved by librarians before
publishing. An external dictionary can be installed in the Koha system. It serves as a whitelist
and help librarians to verify terms added by users.
The 307 libraries, including 218 public, 62 academic, and 27 school libraries, are taken from
Library Technology Guide (Breeding, 2012) for the survey. It is the most comprehensive and
complete list of Koha users published so far. The first step in the survey was to check 307
OPACs to determine how many have enabled tagging. Figure 4 is a breakdown of the 307 Koha
users by library type based on presence or absence of tagging function in the OPAC. Figure 5
displays the same statistics by bar chart.
Tags are enabled in 107 public libraries, almost half of the total 218. The percentage is higher for
academic libraries at 58%. But fewer school libraries, only 22%, allow users to create tags. On
average, 49% of libraries allow their users to create tags, or add their own subject terms for
library materials while 51% of libraries turned off the tagging function.
5
Figure 4. Tagging in 307 Koha OPACs by Type of Libraries
Library Type
Total Libraries
Total Libraries
(Tags Enabled)
Percentage
(Tags Enabled)
Total Libraries
(Tags Disabled)
Percentage
(Tags
Disabled)
Public
218
107
49.08%
111
50.92%
Academic
62
36
58.06%
26
41.94%
School
27
6
22.22%
21
77.78%
All Libraries
307
149
48.53%
158
51.47%
Figure 5. Tagging in 307 Koha OPACs by Types of Libraries
90.00%
80.00%
70.00%
60.00%
50.00%
40.00%
30.00%
20.00%
10.00%
0.00%
Percentage (Tags
Enabled)
Percentage (Tags
Disabled)
Users and folksonomies
How much did users take advantage of the opportunity for tagging? Around 50% of the sample
libraries allow users to add their tags to Koha online catalog. In some libraries, users added their
tags to catalogs actively, and created “large clouds”. But in other libraries, users added only a
few tags.
Tag clouds by the 307 libraries are grouped into 4 categories: large cloud, small cloud, empty
cloud, and no cloud. A “large cloud” includes over 50 tags, and a “small cloud” includes less
than 50 tags. An “empty cloud” has no tags in it. That means users did not add any tags even
though librarians turned on tagging function. The last category “no cloud” means that librarians
did not turned on Tagging in system.
Figure 6 is a summary of 149 libraries that turned on tagging in Figure 4 and 5. About 40% have
large clouds while 46% have small clouds and 14% have empty clouds. Large clouds can be used
as subject access to collections. Small and empty clouds are generally useless. Authors found
that users in 40% of the sample libraries are interested in tagging, and trying to describe library
resources in their own language. They are trying to build their own access points in library
6
catalog. In 60% of the sample libraries, users did not pay attention to tagging. They may even not
be aware of the existence of tagging capability in a catalog.
Figure 6. 149 libraries with Tagging Turned on
Cloud type
Large Cloud
Small Cloud
Empty Cloud
Total
Number of libraries
60
68
21
149
Percentages
40%
46%
14%
100%
Figure 7 is a summary of tag clouds of all the 307 libraries. About 51% of libraries turned off
tagging and therefore have no tag clouds. 22% of libraries have small insignificant clouds which
are almost useless as subject access. Only 20% of them have large clouds that are highly
effective in retrieving materials. We may safely conclude that around 20% of libraries are using
tags as subject search keys. Some tag clouds reside in user accounts behind login and some in
public such as published clouds in OPACs. Even though almost half of the 307 Koha libraries
encouraged users to participate in tagging by turning the function on, 7% of the libraries did not
receive any tags from users. Figure 8 is a graphical summary of the same data as in Figure 7.
Figure 7. Tag Clouds in 307 Koha Libraries
Library
Type
Total
Libraries
Tag Cloud
> 50 tags
Percentage
> 50 tags
Tag Cloud
< 50 tags
Percentage
< 50 tags
Tag Cloud
zero tag
Percentage
zero tag
Tag Cloud
turned off
Percentage
no tag cloud
Public
218
58
26.61%
38
17.43%
11
5.05%
111
50.91%
Academic
62
2
3.23%
27
43.55%
7
11.29%
26
41.93%
School
27
0
0.00%
3
11.11%
3
11.11%
21
77.78%
All
307
60
19.54%
68
22.15%
21
6.84%
158
51.47%
Figure 8. Tag Cloud in 307 Koha Libraries
Tag Cloud in 307 Libaraies
Large Tag Cloud
(over 50 tags)
20%
Small Tag Cloud
(less than 50 tags)
51%
22%
Empty Tag Cloud
(no tags)
Tag Cloud not
turned on
7%
7
Figure 9 is a comparison by library type. Even though more academic libraries allow their users
to add tags (58% vs. 48% for public libraries), they have very few large clouds in academic
OPACs. Academic library users are not so active in adding tags to catalogs. In contrast, users in
public libraries are more active in adding and using tags, which led to more large clouds.
Figure 9. Tag Cloud in Koha Libraries – A Comparison
90.00%
80.00%
70.00%
60.00%
50.00%
40.00%
30.00%
20.00%
10.00%
0.00%
Percentage (> 50 tags)
Percentage (< 50 tags)
Percentage (no tags)
Percentage (tags
disabled)
Public
Academic
School
Tag Cloud in Public Libraries
Public library users are more active than academic or school library users in adding tags to online
catalog. Figure 10 describes tag clouds in 218 public libraries. Around 27% of 218 public
libraries have large tag clouds so that patrons can use them to search the entire catalog. 17% have
small tag clouds. As some small tag clouds include only one or two tags which are not useful. 5%
of the public libraries do not have any user added tags and the rest (about 51%) did not enable
tagging in their system.
Figure 10. Tag Clouds in 218 Public Libraries
Tag Cloud in Public Libraries
Large Tag Cloud
(over 50 tags)
27%
Small Tag Cloud
(less than 50 tags)
51%
Empty Tag Cloud
(no tags)
17%
Tag Cloud not
turned on
5%
8
Some tags are very close to subjects or keywords, such as “nature”, “religion”, or “web 2.0”. But
most tags created by public library users may describe resources for the use of certain
communities, or only themselves, such as “Summer Reading Club”, “Toddler Time”, or “Great
Movies”.
Tag Cloud in Academic Libraries
Most academic library users are not creating large tag clouds. Figure 11 illustrates tag clouds in
62 academic libraries. Only a small portion of academic libraries, 3%, enjoy large tag clouds. 44%
of them have small tag clouds, and 11% have an empty tag cloud. 42% of 62 academic libraries
did not turn on tagging. Only a few academic libraries are actually using tag clouds for searching
in catalog.
Figure 11. Tag Cloud in 62 Academic Libraries
Tag Cloud in Academic Libraries
3%
Large Tag Cloud (over
50 tags)
42%
44%
Small Tag Cloud (less
than 50 tags)
Empty Tag Cloud (no
tags)
Tag Cloud not turned
on
11%
Tag Cloud in School Libraries
Figure 12 shows tag clouds in school libraries. The majority of school libraries did not turn on
tagging. Only 11% of school libraries have small tag clouds. Each “cloud” includes one or two
tags at most. Essentially, school libraries do not use tagging at all. More research is needed to
look into the reason behind this phenomenon.
9
Figure12. Tag Cloud in 27 School Libraries
Tag Cloud in School Libraries
0%
Large Tag Cloud (over
50 tags)
11%
11%
Small Tag Cloud (less
than 50 tags)
Empty Tag Cloud (no
tags)
78%
Tag Cloud not turned
on
Conclusion
Research provided evidence in support of folksonomies as a viable alternate subject access to
resources. Very few legacy or classic ILSs are capable of this function. The next generation ILS,
Koha, is an exception. Only half of newly developed discovery tools (47%) allow tagging. To get
a glimpse of how much libraries are taking advantage of a system with tagging capability, the
authors used Koha as an example and found that only half of the libraries (49%) enabled tagging.
Among the user libraries that enabled tagging, only 40% have large tag clouds that appear useful,
while 46% do not have adequately meaningful clouds (small clouds) and 14% have given users
the opportunity to add tags, but users did not show any interest, thus resulting in empty clouds.
Based on the above findings, the authors recommend that more vendors should add tagging
capability in the future release of new systems. Those systems with tagging should refine it for
better access to collections. Libraries should find ways to more aggressively promote tagging
activities. Research should be done to investigate why half of the libraries do not allow users to
add tags and why academic library users are less interested in tagging than public library users.
Tagging is a Web 2.0 phenomenon where user participation is anticipated. It is only right that we
allow users to share their wisdom in cataloging.
10
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12