Social Networks

Outline

• Introduction

• Origin of Social Networks

• Social Network Analysis

• Types of Social Networks

• References

What is social network?

• Wikipedia definition-A social network is a social structure made of individuals (or organizations) called "nodes," which are tied (connected) by one or more specific types of interdependency, such as friendship, kinship, financial exchange, dislike or relationships of beliefs, knowledge or prestige

• Social networking is the grouping of individuals into specific groups, like small rural communities or a neighborhood subdivision, if you will.

Social Networks

• Not a new concept, (6 degrees of separation)• Ramsey theorem-At any party with at least six

people, there are three people who are all either mutual acquaintances or mutual strangers

• People typically maintain 10-20 close relationships among thousands of acquaintances

• Metcalf’s Law – value of a network increases n2 to # of participants– Not exactly, but in theory.– Dependent upon interaction model

Online social networking

• Social sites commonly used.

• Online community of internet users

• Common interests in hobbies, religion, or politics.

• Socialize on sites by reading the profile pages of other members and possibly even contacting them. 

Origin of social sites

• Social network sites (SNSs) such as such as Friendster, CyWorld, and MySpace allow individuals to present themselves, articulate their social networks, and establish or maintain connections with others.

• These sites can be oriented towards work-related contexts (e.g., LinkedIn.com), romantic relationship initiation (the original goal of Friendster.com), connecting those with shared interests such as music or politics (e.g., MySpace.com), or the college student population (the original incarnation of Facebook.com).

Popular social networking sites

• Personal sites-Myspace,orkut,Cyworld

• Professional/work related-LinkedIn

• Romantic relationship initiation-friendster

• Microblogging-Twitter

• Music-last.fm

• Movies-flickster

• Photos/pictures-flickr

Social Network Analysis

We measure Social Network in terms of:1. Degree Centrality: The number of direct connections a

node has. What really matters is where those connections lead to and how they connect the otherwise unconnected.

2. Betweenness Centrality: A node with high betweenness has great influence over what flows in the network indicating important links and single point of failure.

3. Closeness CentralityThe degree an individual is near all other individuals in a network (directly or indirectly). It reflects the ability to access information through the network .

Why internet is popular mean for social networking

• The Internet is powerful because it bridges distance at a low cost

• When people first meet online they tend to “like” each other more

• Less stressful than face-to-face meeting• Superficialities aside people focus on

communicating their “selves”

Social network as a graph

• Nodes: A Unit That Possibly is Connected

• Individuals, Households, Workgroups , Organizations, States

• Relationships (A Specific Type of Connection)

• A “Role Relationship”

• Gives Emotional Support

• Links Web Page

Social network as a graph(conti.)

• Ties (Contain One or More Relationships)

• Friendship (with possibly many relationships)

• Affiliations (Person – Organization)

• Works for IBM; ACM Member; Football Team

• One-Mode, Two-Mode Networks

An example of a social Network diagram. The node with the highestBetweenness centrality is marked in yellow.

A Network is More Than The Sum of Its Ties

• A Network Consists of One or More Nodes Could be Persons, Organizations, Groups, Nations, Web Connected by One or More Ties

• Could be One or More Relationships That Form Distinct, Analyzable Patterns

• Can Study Patterns of Relationships OR Ties• Emergent Properties

Types of social networkers

• Alpha Socialisers – (a minority) people who used sites in intense short bursts to flirt,meet new people, and be entertained.

• Attention Seekers – (some) people who craved attention and comments from others,often by posting photos and customising their profiles.

• Followers – (many) people who joined sites to keep up with what their peers were doing.

Types of social networkers(conti.)

Faithfuls – (many) people who typically used social networking sites to rekindle old friendships, often from school or university.

• Functionals – (a minority) people who tended to be single-minded in using sites for a particular purpose.

Source: Ofcom Social Networking Sites research, September-October 2007

Privacy concerns

• Social networking sites provide privacy options but users are generally unaware or tend to ignore such concerns

• Stalkers, terrorists, ill-doers, con-artists could benefit from such issues

• Recent scandals-England :MI-6’s director’s wife puts up photos of family on facebook.

• Facebook’s controversial decision to make visible relationship actions to entire social group

Security issues

• Recent malware exploiting social networks– Malicious Banner ads– Adware– Phishing attacks– Customizable scripts

Social and Psychological issues

• Increasing relationships but decreasing intimacy