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Online Social Networks
Modified from Philipa Gill
CPE 401 / 601 Computer Network Systems
Mehmet Hadi Gunes
Basic definitions• Network: (net + work, 1500’s)
• Noun:– Any interconnected group or system– Multiple computers and other devices connected together
to share information
• Verb:– To interact socially for the purpose of getting connections or
personal advancement– To connect two or more computers or other computerized
devices
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What is a Social Network ?
• Network – a set of nodes, points or locations connected
• Social Network - a social structure made up of individuals (or organizations) called "nodes", which are tied (connected) by one or more specific types of interdependency, such as friendship, common interest
• Online Social Networks – Platforms to build social networks among people who share interest, backgrounds, or real life connections
Source: Wikipedia
What are (Online) Social Networks?
• Social networks are graphs of people– Graph edges connect friends– `Friend’ has different implications– How hard is it to be Facebook `friends’?
• Online social networking– Social network hosted by a Web site– Friendship represents shared interest or trust– Online friends may have never met
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http://soshable.com/twitter-vs-facebook-across-the-web/
• Facebook – befriend me
• Twitter – I follow you; you follow me
• Flickr – ‘just post it’
Friendship Establishment
Social Networks• Links denote a social interaction– Networks of acquaintances– collaboration networks• actor networks• co-authorship networks• director networks
– phone-call networks– e-mail networks– Bluetooth networks– sexual networks– home page/blog networks– …
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Popular social networking sites• Art – devianART• General – Facebook, Google+, Qzonr• Microblogging – Twitter, Reddit, Sina, Tumblr• Movies – flickster, YouTube• Music – last.fm, Vkontakte• Personal sites – Myspace, Mylife, Cyworld• Photos/pictures – Flickr, Instagram, Pinterest• Professional – LinkedIn, Academia• Relationship initiation – Friendster
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Social Network Usage
Social Media is
• Consumer generated media It is media that is designed to be shared, sharing means that it is easy to comment on, that it is easy to send, there are no costs associated with viewing the media and last but not least it is always available.
• Social media enables people to share information with friends and colleges using the Internet
Social Networking
Friendship
• Keeping in Touch
• Developing new relationships
Sharing
• Photos• Links• Interests
Community
• Causes• Beliefs• Advocacy
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Social Network Statistics• Facebook
– Worldwide, there are over 1.19 billion active Facebook users• Source: Facebook
– 4.5 billion likes generated daily as of May 2013 which is a 67 percent increase from August 2012 • Source: Facebook
– There are 874 million mobile active users which is a 45 percent increase from 2012• Source: Facebook
– 50% of 18-24 year-olds go on Facebook when they wake up• Source: The Social Skinny
– One in five page views in the United States occurs on Facebook • Source: Infodocket 2012
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Social Network Statistics• Twitter
– 230+ million monthly active users
– 500 million Tweets are sent per day
– 76% of Twitter active users are on mobile
• Google+– ~ 540 million registered users,
300 million people active in stream
– Over 1.5 Billion photos uploaded every week to Google+ photos
• Linkedin– More than 259 million members
in over 200 countries– Professionals are signing up to
join LinkedIn at a rate of more than two new members per second
• Instagram– Over 100 million users,– total, 40 million photos are
uploaded to Instagram every single day according to a report by Nielsen.
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Online social network use
• Fixed broadband (Sandvine Q1 2014)• YouTube 5.5% upload, 13.2% down • Facebook 2.2% upload, 2.0% down
• Popular with users on the go– Mobile (Sandvine Q1 2014)• YouTube 3.8% up, 17.6% down• Facebook 27.0% up, 14.0% down
Social Networks
• Not a new concept, (6 degrees of separation)• People typically maintain 10-20 close
relationships among thousands of acquaintances
• The vast majority of people report the opinion they trust most is from ‘someone like me’. – For the first time in our history, peers have bested
the wisdom of experts
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Why are social networks interesting?
• Popular way to connect– Estimated 1.32B users online each day– Average American spends 40 minutes/day on the
site• Changing the flow of information– Formerly few ``writers’’ many ``readers’’ online– Now anyone can write! – What does this mean for Internet traffic?
• Useful in times of disaster
Social networks: Interdisicplinary Field
• social network analysis is an interdisciplinary social science; – Sociologists, computer scientists, physicists and mathematicians have
made large contributions to understanding networks in general (as graphs) and thus contributed to an understanding of social networks
• [Social network analysis] is grounded in the observation that social actors [i.e., people] are interdependent and that the links [i.e., relationships] among them have important consequences for every individual [and for all of the individuals together]. ... [Relationships] provide individuals with opportunities and, at the same time, potential constraints on their behavior. ... Social network analysis involves theorizing, model building and empirical research focused on uncovering the patterning of links among actors. It is concerned also with uncovering the antecedents and consequences of recurrent patterns.
Linton C. Freeman
Social Network Examples• Effects of urbanization on individual well-
being• World political and economic system• Community elite decision-making• Social support, Group problem solving• Diffusion and adoption of innovations• Belief systems, Social influence• Markets, Sociology of science• Exchange and power• Email, Instant messaging, Newsgroups• Co-authorship, Citation, Co-citation• SocNet software, Friendster• Blogs and diaries, Blog quotes and links
Social Networks Basic Questions
• Balance: important in exchange networks– In a two-person network (dyad), exchange of goods, services and cash
should be balanced. – More generally, exchanges of “favors” or “support” are likely to be
quite balanced.
• Role: what role does the actor perform in the network?– Role is defined in terms of Actors’ neighborhoods.– The neighborhood is the set of ties and actors connected directly to
the current actor. – Actors with similar or identical neighborhoods are assigned the same
role.
• Paradigm: interchangability. Actors with the same role areinterchangable in the network.
Social Networks Basic Questions
• Prestige: How important is the actor in the network? – Related notions are status and centrality.
• Centrality reifies the notion of “peripheral vs. central participation” from communities of practice. – Key notions of centrality were developed in the 1970’s, e.g.
“eigenvalue centrality” by Bonacich.
• Most of these measures were rediscovered as quality measures for web pages:– Indegree– Pagerank = eigenvalue centrality– HITS ?= two-mode eigenvalue centrality
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How are links distributed
Mislove et al. 2007
• Broadcasters• News outlets,
radio stations• No reason to
follow anyone• Post playlists,
headlines
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User relationships on Twitter
Mislove et al. 2007
• Acquaintances• Similar number
of followers and following
• Along the diagonal
• Green portion is top 1-percentile of tweeters
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User relationships on Twitter
Mislove et al. 2007
• Miscreants?• Some people
follow many users (programmatically)
• Hoping some will follow them back
• Spam, widgets, celebrities (at top)
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User relationships on Twitter
Mislove et al. 2007
On User Arrival - MySpace
Public users
What does user ID say about account creation time? Plot user ID vs. last login of that user for all our users
Private users
Torkjazi et al 2009
On User Arrival - MySpace• 32% of public and 18% of private users are tourists• Discovery of “tourists” enables accurate estimation
of user account creation time based on their associated user ID
Tourists
“Clean edge”=
users whose last login
is shortly after their account creation
time=
“MySpace tourists”Torkjazi et al 2009
On User Departure - MySpace
More public and private profiles in the first half of ID space
More invalid profiles in the second half of ID space
Users joining the system earlier have been more likely to keep their accounts than newer users
Are newer users more likely to leave than older ones?
Torkjazi et al 2009
MySpace Life Cycle
• Slow-down in the growth rate of MySpace is related to emergence of Facebook
• Informal evidence (Alexa.com): Daily accesses to Facebook surpassed that of MySpace, at around April 2008
Possible reasons behind MySpace’s decline?
Torkjazi et al 2009
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Categories of pages
Schneider et al 2009
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Session Characteristics
Schneider et al 2009
HTTP Traces
Schneider et al 2009
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Action popularity
Schneider et al 2009
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Feature sequences
Schneider et al 2009
Types and Amounts of Info. Disclosed
Gross et al 2005
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Picture Posting Pattern
0.25 2.5 25 250 25001
10
100
1000
Number of posts
Phot
o Si
ze (K
B)
Erdin et al 2014
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Video Posting Pattern
0.21 2.1 21 21010
100
1000
10000
100000
Number of posts
Vide
o Si
ze (K
B)
Erdin et al 2014
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Non-Multimedia Post Frequency
55 60 65 70 75 80 85 90 95 1000.499999999999999
4.99999999999999
49.9999999999999
499.999999999999
Posting Events
Number of Online Friends
Num
ber o
f Non
-Mul
timed
ia P
osts
Erdin et al 2014
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Multimedia Data to DownloadAs the time between logins increases, the total amount of data the user might download from friends increases. In extreme cases, it is observed 1GB of data when the user has not logged in for about a day.
0.01
0.1
1
10
100
1000
0.010.1110
Tota
l Si
ze (M
B)
Time between Logins (Hours)
Photo and Video Posts Between Logins
Erdin et al 2014
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OSNs: Wrap up• Many different types of OSNs– Photos, video, profile-based
• Some extremely popular source of much Internet traffic– Facebook, YouTube
• New ones emerging– Instagram, snapchat
• Old ones fading– MySpace, Friendster
• Studying their properties can inform how we build networks and systems to support them!
