Understanding Cross-site Linking inOnline Social Networks

Yang Chen1, Chenfan Zhuang2, Qiang Cao1, Pan Hui3

1Duke University2Tsinghua University

3Hong Kong University of Science and Technology

Motivation

• A number of OSN sites with different functionality

• It is quite common for an individual user to have multiple accounts on different OSN sites.– How to efficiently manage accounts on different OSNs?

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Interact with friends Share breaking news

Job search Location-centric social interactions

The Cross-site Linking Function

The cross-site linking function allows a user to link her account on one OSN site to her accounts on other OSN sites

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Cross-site Linking: Advantages

• Make cross-site content posting easy– Help Foursquare users automatically post tips to Facebook and Twitter

• Avoid repeated efforts in social connection establishment– Import the contact list from other OSNs

• Provide more information of a user– Visit the linked profiles on other OSNs

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Why Foursquare?

• A representative LBSN service, one of the most popular OSN sites– Foursquare app: customized discovery and

recommendation engine– Swarm app: real-time location sharing with friends

• Supports the cross-site linking function– A user can link his profile to Facebook/Twitter

• Every Foursquare user has a public profile page (http://foursquare.com/user/ID/)

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Data Collection

• Goal: analyze the entire Foursquare user base– To avoid the disadvantages of biased sampling

• Challenge: IP-based rate limiting– Crowd crawling:100 crawlers around the United States,

each crawls one chunk of IDs• Data– Collected between Jul. 22th, 2014 and Jul. 29th, 2014– Public profiles of 51.15 million Foursquare users

• Almost all (if not all) Foursquare users

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ID Gender Tips Checkins Friends Facebook Twitter …

123 male 5 28 10 15576473 eric_c …

Linking Options

Twitter Facebook Linking Option PercentageYes No TW only 3.82%No Yes FB only 44.19%Yes Yes FB+TW 11.96%No No Neither 40.03%

• About 60% Foursquare users have enabled the cross-site linking function

• 56.15% users have added their Facebook accounts• 15.78% users have added their Twitter accounts

The cross-site linking function is widely used among Foursquare users7

Percentage Distribution of Linking Options

Group-based Analysis: Gender

Very little difference between male users and female users in terms of the distribution of linking options

Gender options: 51.52% Male 42.92% Female 5.56% Rather not say

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Group-based Analysis: Country

Top four countries: USA (27.61%) Turkey (9.49%) Indonesia (8.17%) Brazil (7.04%)

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Country BRA IDN TUR USA

Percentage 82.25% 50.51% 80.33% 50.33%

Percentage of users that have enabled cross-site linking

Group-based Analysis: Activity

• Two factors: social connections and location-centric activities (leaving tips, check-ins)

# of Friends # of Checkins and Tips Group Percentage=0 =0 Zombies 28.23%=0 >0 Loners 9.50%>0 =0 Watchers 14.02%>0 >0 Ordinary users 48.25%

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Group-based Analysis: Activity (cont.)

Most zombies/loners have not enabled cross-site linking, as they are socially isolated. Watchers v.s. Orindary users

Watchers are less motivated to link to Twitter, as they don’t publish 73% watchers and 71% ordinary users have linked to Facebook (users from both

groups are connected with other Foursquare users)11

Behavioral Difference among Users with Different Linking Options

• Users who have enabled the cross-site linking function are more “active”– Cross-site linking will deliver published contents to more prospective audience

• “TW only” > “FB only”– Publicly viewable tweets can be quickly spread through the Twitter network– FB user status is only visible to friends by default (fewer possible audiences)12

User Privacy Concerns & Cross-site Linking

Profile Picture

Gender Residential Location

Last Name Biography

Enabled (%) 66.99% 94.44% 91.68% 94.61% 3.29%

Disabled (%) 33.01% 5.56% 8.32% 5.39% 96.71%

In Foursquare, users can customize their profiles according to privacy concerns (a user can choose whether to enable an optional field)

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Alice’s Foursquare Profile

Alice’s Facebook Profile

Alice’s Twitter Profile

More information about Alice!!

Intuitively, cross-site linking might cause concerns for users who care a lot about their privacy.

User Privacy Concerns & Cross-site Linking (cont.)

Whether or not uploading personalized profile photo is an indicator for the adoption of cross-site linking

Enabling any of the five optional field indicates a higher probability of using the cross-site linking function

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Cross-site Information Consistency

First Name Last Name Gender

Percentage of users who have entered identical information in a selected filed

89.84% 87.02% 99.30%

Cross-site Information Consistency (“Foursquare-Facebook”)

Users have a high probability to manifest cross-site information consistency

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A user might choose to expose the same or different personal information on different sites

Cross-site Information AggregationUser Info

Foursquare Twitter

ID Gender Tips … ID Tweets Lists …

USER A 1 m 10 … 1982 100 17 …

USER B 2 f 20 … 34 5 0 …

USER C 5 f 0 … 19903 20 1 …

USER D 9 m 7 … 563122 7 4 …

… … … … … … … … …

• Aggregate the information of the same user from different OSN sites (learn more about a user)

• Applications: friend suggestion, point-of-interest recommendation, personalized advertising, …

• Example: gender-based analysis of Twitter16

Gender-based Analysis of Twitter

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Female users publish more tweets Male users are involved in more lists

Gender-based Analysis of Twitter (cont.)

URL Description Location

Male 32.07% 62.82% 56.87%

Female 25.02% 64.73% 57.35%

The Use of Optional Fields (%)

Male users have a higher probability to add a URL Both male and female users have a nearly 63%

probability of adding a description, and a nearly 57% probability to add the location information.

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Related Work• Cross-OSN linking papers

– Ottoni et al. [ICWSM 2014]: Pinterest-Twitter linking– Chen et al. [WOSN 2012]: Google+– Both of them used biased sampling methods, while our study is based

on the entire Foursquare user population• Wang et al. [IEEE Internet Computing, 2014] compared a series of user

activities across Foursquare, Facebook, and Twitter– We focus on the cross-site linking function

• Goga et al. [WWW 2013], Liu et al. [SIGMOD 2014] investigated how to identify accounts on different OSNs that all are owned by the same user– Useful for the OSN sites which do not support the cross-site linking

function

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Conclusion

• About 60% of Foursquare users have enabled the cross-site linking function, and these users are more active than other users

• Adding contents to an optional field indicates a higher probability of activating the cross-site linking function

• If a Foursquare user has linked his account to Facebook, he will have a high chance to provide consistent information to both Foursquare and Facebook

• The use of cross-site information aggregation helps us investigate the gender difference in using Twitter

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Future Work

• Investigate cross-site links among more mainstream OSN sites– Discover general patterns to characterize cross-OSN links

• A volunteer-based study – Access the non-publicly viewable data (e.g.: check-in

history) a deeper investigation into cross-site information aggregation

• Build practical services/applications based on cross-site links– Malicious account detection

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