Flickr Tags Network Mustafa Kilavuz

Tags A tag is a keyword Search, spam detection, reputation systems, personal organization and metadata

Usage Social bookmarking ◦ Personal bookmarks ◦ Allows users to store and retrieve resources Social tagging systems ◦ Shared tags for particular resources ◦ Each tag is a link to additional resources tagged the same way by other users ◦ Folksonomy: popular tags

Youtube

Delicious

Last.fm

Last.fm

Last.fm

Flickr

Vocabulary Problem Different users use different terms to describe the same things Polysemy: A single word has multiple meanings Synonymy: Different words have the same meaning Abstraction: Tagging a resource in different levels of abstraction ◦ Animal, cat, Persian cat, Felis silvestris catus longhair Persian Different languages Missing context: Tags that could not be related with the images by others ◦ Holiday, me, friends, a person’s name

Tag Usage on Flickr The tag usage is not mandatory in Flickr. User can tag their friends’ photos. But within 58 million tag observed, the overwhelming majority are owner tags. Most people has very few distinct tags while a small group has extremely large sets of tags.

Tag vocabulary size across the set of users

Growth of distinct tags 10 users are randomly chosen ◦ Frequent uploaders ( > 100 photos) ◦ Frequent taggers ( > 100 tags) The number of distinct tags are observed as the number of photos uploaded increases.

Growth of distinct tags

Vocabulary Formation Vocabulary overlap distribution for random users and contacts

Tag frequency distribution in Flickr

Number of tags per photo in Flickr

Information from a Flickr Photo Useful ◦ User ◦ Upload date ◦ Tags ◦ View count ◦ Groups Other ◦ Title ◦ Description ◦ Comments

Data Extraction Method Iterate on each user ◦ Iterate on each public photo of the user ◦ Get all contacts and group information Iterate on each group ◦ Iterate on each photo in the group

Tripartite Network Model page person tag Can project onto bipartite graphs person – tag tag – page person – page Can project onto one-mode graphs person – person tag – tag person - page From Lada Adamic

A bipartite model

Tag Network Model Building Sky Light Blue Cloud Window

aTagsLife

Geotags Additional place information Spatial distribution, places ◦ San Francisco, museum Temporal distribution, events ◦ Burst of tagging in a small time interval

Clusters Strongly connected tags Flickr uses for years for searching

What we can do.. Investigate clusters to get information about ◦ Events and their relations ◦ Interests and their relations ◦ Etc.

Tag Categories

QUESTIONS?