This document discusses social tagging and compares three social networks: Delicious, Flickr, and YouTube. It finds that Delicious users tag primarily to organize bookmarks about web content and programming. Flickr users tag mainly to organize photos by features like color and location. YouTube users do not tag as much and tagging seems to focus on describing video content. The tagging behavior, vocabulary, and trends differ across these three social networks.

1. Perspectives on Social Tagging Ying Ding SLIS Indiana University [email_address]

3. UTO Tag ging Comment Source Tagger (Foaf:Agent) Object has_source Vote has_creator has_vote has_tag Date Tag has_ comment has_ relatedTag has_ date has_ object

4. Crawled Tags Social Network Objects Taggers Tags Tag/Object Tag/Tagger Object/Tagger Delicious 996,748 2,787,860 9,282,058 9.31 3.33 0.36 Flickr 295,837 153,778 1,351,201 4.57 8.79 1.92 YouTube 527,924 185,975 1,443,924 2.74 7.76 2.84 Total 1,820,509 3,127,613 12,077,183 5.54 6.63 1.71

5. Delicious Rank 2005 2006 2007 1 blog blog blog 2 programming programming design 3 software software software 4 music design programming 5 design reference reference 6 web music tools 7 reference web Web2.0 8 java tools web 9 art art video 10 tools java music 11 linux video art 12 news Web2.0 linux 13 xml linux webdesign 14 science news howto 15 search tutorial free 16 games howto tutorial 17 research imported news 18 technology development development 19 security research opensource 20 video internet java

6. Flickr Rank 2005 2006 2007 1 2005 usa 2007 2 d70 california canon 3 tsimshatsui 2006 nature 4 hongkong cameraphone autumn 5 nightview celltagged art 6 germany zonetag nikon 7 newkie sanfrancisco water 8 ragbrai blue bw 9 art light red 10 wonder sky blue 11 night urban sky 12 buttersweet red japan 13 15fav sea fall 14 central me beach 15 light water portrait 16 marco nature london 17 london marco night 18 apargioides london green 19 orange green usa 20 ads1 music november

7. Youtube Rank 2005 2006 2007 1 music the the 2 funny funny music 3 video music funny 4 the video video 5 dance live girl 6 crazy of of 7 commercial comedy sexy 8 live dance live 9 dancing rock dj 10 guitar cat 2007 11 fun halloween dance 12 AMV love hot 13 girl girl comedy 14 japan movie rock 15 hot dj love 16 anime in and 17 Halloween sexy sex 18 halo and in 19 of fight new 20 cat you cat

8. Tagging preference Tagging Features Tag Examples Time 2005, 2006, 2007, November Geo-location Africa, America, Amsterdam, Berlin, Argentina, Japan, China, Chicago, Chile, England Scientific domains bioinformatics, biology, ecology, ecommerce Religion Bible, Buddhism, Christianity, Islam Programming ajax, algorithm, C, C++, eclipse, hp, ibm, intel, j2ee, java, javascript, lisp, perl, python, ruby IT database, datamining, enterprise2.0, itunes, ontology, owl, rdf, semanticweb, semweb, wordpress, xml, xslt Company apple, amazon, ebay, google, Microsoft, nokia, Nikon, oracle, w3c, yahoo Opinion bad, cool Colour black, bw, dark, white Name/Celebrity Britney, Spears, Bush, George, james, john, Michael, David Social networks facebook, flickr, secondlife, youtube, Delicious, Wikipedia, myspace

9. Tagging variation Tag variation Tag Examples Plural vs. Singular animal(s), application(s), band(s), boy(s), car(s), cartoon(s), cat(s), girl(s) Conjunction, prepositions, etc. and, at, all, for, from, of, on, one, out, the, to Acronyms and abbreviations api, au, apps, bw, cms, cs, css, de, dc, dhtml, dj, diy, dns, dom, drm, dvd, el, en, fanfic, gps, gui, hci, hdr, hp, nyc, rss, rpg, Compound words audiobooks, blackandwhite, cameraphone, celltagged, creativecommons, datamining, dotnet, enterprise2.0, filesharing, filesystem, firefox:bookmarks, firefox:rss, firefox:toolbar, googlemaps, graphicdesign, howto, losangeles, newmedia, newyork, projectmanagement, rubyonrails Variant spellings and languages color/colors/colour, cultura, economica, educacion, foto, fotographia, fotos, het, humor/humour, musik, musica Variant word forms Blog/blogger/blogging/blogs, bookmarking/bookarmks, barsil/brazil, conversion/convert/converter, el/elearning/e-learning, hack/hacking/hacks, lifehack/lifehacker/lifehacks, newyork/nyc, opensource/open-source, podcast/podcasting/podcasts, process/processing, product/production/productivity/products, san-sanfrancisco/sf, tag/tags/tagging

10. Social tagging features of these three social networks Social network features delicious flickr youtube Community People interested in sharing bookmarks about web and programming People interested in sharing photos including professional and non-professional photographers People interested in sharing video on any subject. Main topics Web, programming, video, music, news Colour, location, year, seasons Music, video, funny things, sexy and girl Tagging behaviour One of the key activities – many tagging Not many tagging Not many tagging Dynamic yes no no Emerging topic (trend) Webdesign, free, web2.0 no no Declining topic Internet, research, xml, security no no Stability Tag set is changing with average 10%-20% in each year Tag set is stable Tag set is stable Tagging vocabulary stable stable stable Tagging focus content of the bookmark feature of the photo content of video Tagging purpose organizing and sharing Organizing (mainly) Commenting (mainly)? Tagging 725%(2006/2005), 2730%(2007/2205), 357%(2007/2006) 585%(2006/2005), 47540%(2007/2005), 9882%(2007/2006) 8400%(2006/2005), 24900%(2007/2005), 290%(2007/2006)