Social Network Technologies


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slides for our class on Feb. 6th, 2008.

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Social Network Technologies

  1. 1. Social Network Technologies Dr. Harry Chen CMSC 491/691S February 6, 2008
  2. 2. Agenda <ul><li>History and Motivation </li></ul><ul><li>Analyzing social networks </li></ul><ul><li>Languages for describing social networks </li></ul><ul><li>Programming API for building social networks </li></ul>Source:
  3. 3. Social Network sites <ul><li>What’s a Social Network site? </li></ul>
  4. 4. Let’s define “Social Network sites” <ul><li>A web site that allows individuals to </li></ul><ul><ul><li>Construct a public or semi-public profile in a bounded system </li></ul></ul><ul><ul><li>Articulate a list of other users with whom they share a connection </li></ul></ul><ul><ul><li>View and traverse their list of connections and those made by other with the system </li></ul></ul>Source: Social Network Sites: Definition, History, and Scholarship , D. Boyd and N. B. Ellison
  5. 5. Why do people join Social Network sites? <ul><li>To social </li></ul><ul><ul><li>“ Since we can’t meet face-to-face, we may well just meet up online.” </li></ul></ul><ul><li>To share experience </li></ul><ul><ul><li>“ I have some great pictures from Tibet for you to see.” </li></ul></ul><ul><li>Being nosy </li></ul><ul><ul><li>“ Who is that cute girl I saw in the gym?” </li></ul></ul><ul><li>Find contacts and make deals </li></ul><ul><ul><li>“ Maybe Bob can introduce me to that VC” </li></ul></ul><ul><li>Let your voice be heard </li></ul><ul><ul><li>“ My friends don’t’ listen to me. Maybe others will.” </li></ul></ul>Do you have other reasons to join a social network?
  6. 6. Looking back into the past The idea of creating profiles and communicate with strangers are nothing new. Remember ICQ, IRC and MUD. What do you think have caused the sudden explosion of Social Network sites? Source: Social Network Sites: Definition, History, and Scholarship , D. Boyd and N. B. Ellison
  7. 7. What does it all mean?
  8. 8. Social Network Analysis <ul><li>The study of relationships between people, groups, organizations, computers, web sites, and other information and knowledge processing entities. </li></ul>Why do you think it’s important to study social relationships? Source: Social Network Analysis, A Brief Introduction
  9. 9. Key concepts <ul><li>Social network as a graph </li></ul><ul><ul><li>People  Nodes </li></ul></ul><ul><ul><li>Relationships  Edges </li></ul></ul><ul><li>What do we measure? </li></ul><ul><ul><li>Degree </li></ul></ul><ul><ul><li>Closeness </li></ul></ul><ul><ul><li>Betweenness </li></ul></ul><ul><ul><li>Centralization </li></ul></ul><ul><ul><li>Clustering coefficient </li></ul></ul><ul><ul><li>Path length </li></ul></ul><ul><ul><li>Radiality </li></ul></ul>Source:
  10. 10. Example: Betweenness (1) Heather has less direct connection than Diane. (2) Heather has a “sweeter” spot in the network because she connects two groups of people. (3) Heather is a “single point of failure”. Source:
  11. 11. Who is reading your profile? <ul><li>Both humans and machines </li></ul>Got it! Contact, school, favorites… HTML detected. But, what’s in the page? In order to help computer programs to better understand our profiles and social relationships, we need to express information in an explicit representation.
  12. 12. FOAF (Friend-Of-A-Friend) <ul><li>An ontology for describing people and the links between them (i.e., relationships). </li></ul><ul><li>FOAF documents are typically defined in RDF (Resource Description Framework). </li></ul>
  13. 13. An Example: How FOAF works for me FOAF profile crawler
  14. 14. What can you say using FOAF?
  15. 15. FOAF toys <ul><li>Create your own FOAF profile </li></ul><ul><ul><li> </li></ul></ul><ul><li>FOAF Explorer </li></ul><ul><ul><li> </li></ul></ul>
  16. 16. XFN (XHTML Friends Network) <ul><li>A way to represent human relationships using hyperlinks. </li></ul><ul><li>It divides your social relationships into categories: </li></ul><ul><ul><li>People who you are friend with. </li></ul></ul><ul><ul><li>People you have physically met </li></ul></ul><ul><ul><li>People in your professional circles of life </li></ul></ul><ul><ul><li>People relate to you geographically (live together, neighbor) </li></ul></ul><ul><ul><li>Your family members </li></ul></ul><ul><ul><li>People whom you have romantic relationship with </li></ul></ul><ul><ul><li>Identity (ME) – identify web sites that you own </li></ul></ul>XFN:
  17. 17. XFN Examples Step 1: Use “rel” tag to define how you are related to this link. Step 2: Let the world know you an XFN page Read more:
  18. 18. Harnessing the power of Social Networks <ul><li>Why do you think web sites are so in love with social networks? It’s all business! </li></ul><ul><li>Two objectives: </li></ul><ul><ul><li>Grow user base : more visitors, more clicks </li></ul></ul><ul><ul><li>Keep your eyeballs focused : the longer you stay on their pages means more revenues </li></ul></ul><ul><li>Q: How can they achieve these? </li></ul>
  19. 19. Social Network Innovation <ul><li>Approach 1: Provide services that solve an actual problem or add value to users’ Web experience </li></ul><ul><ul><li> – social bookmark </li></ul></ul><ul><ul><li>Flickr – share photos </li></ul></ul><ul><ul><li>MySpace – get musician’s work to the public </li></ul></ul><ul><ul><li>Facebook – 24/7 connect in the cyber world. </li></ul></ul><ul><li>Approach 2: Build a platform and provide API </li></ul><ul><ul><li>Facebook API </li></ul></ul><ul><ul><li>Google OpenSocial API and Social Graph API </li></ul></ul>
  20. 20. Facebook API <ul><li>Facebook provide a platform , something that others can customize (re-program). Most Web 2.0 sites, being applications, they can’t be re-programmed – e.g., flickr. </li></ul><ul><ul><li>Interface (API): GET, POST HTTP calls to fetch/update user and application information </li></ul></ul><ul><ul><li>Query (FQL): SQL-like interface for accessing user and application information </li></ul></ul><ul><ul><li>Markup (FBML): markup language for adding your own applications into Facebook </li></ul></ul>
  21. 21. Criticisms of Facebook API <ul><li>Facebook requires all communication and application interactions “route” through Facebook servers. </li></ul><ul><ul><li>No JavaScript, No DIV </li></ul></ul><ul><li>You are forced to learn a new language: FBML </li></ul><ul><li>Performance suffers because you give up all applications to Facebook </li></ul>
  22. 22. Google’s OpenSocial API <ul><li>A set of common API for building social applications on the Web. </li></ul><ul><li>Get access to </li></ul><ul><ul><li>Profile information (user data) </li></ul></ul><ul><ul><li>Friends information (social graph) </li></ul></ul><ul><ul><li>Activities (things that happen) </li></ul></ul><ul><li>JavaScript and REST </li></ul>
  23. 23. Benefits of using OpenSocial API <ul><li>Developers have to learn one API to work with multiple social network sites. </li></ul><ul><li>No need to learn a new language, if you already know JavaScript. </li></ul><ul><li>Many popular social network sites support OpenSocial API </li></ul>
  24. 24. Criticisms of OpenSocial API <ul><li>The idea only works if everyone support OpenSocial API. Facebook doesn’t support it, but it has a large user base. </li></ul><ul><li>Why new companies want to open up its information to other side? </li></ul><ul><li>OpenSocial API was incomplete and problematic when it was first released. </li></ul>As reported by TechCrunch on November 5, 2007, OpenSocial was also quickly cracked. The total time to crack the OpenSocial-based iLike on Ning was just 20 minutes, according to TechCrunch, with the attacker being able add and remove songs on a user's playlist, and to look into information on their friends.
  25. 25. Google’s Social Graph API <ul><li>API that provide social network information about a Web user. </li></ul><ul><li>Given a Web user ID (email or URL), it can tell you </li></ul><ul><ul><li>Other Web user ID you are known to be associated with (e.g., different web site you own, profiles on different social networks) </li></ul></ul><ul><ul><li>Relationship with other Web users. </li></ul></ul>
  26. 26. OpenSocial vs Social Graph API <ul><li>Both support REST and provides JavaScript API </li></ul><ul><li>Social Graph API doesn’t rely on pre-defined agreements between different social network sites. </li></ul><ul><li>Social Graph rely on Google’s computing power to crawl and process public data on the Web and discover social relationships. </li></ul>
  27. 27. Social Graph API demo http://
  28. 28. Criticisms of Social Network sites <ul><li>People spend too much time on SNs </li></ul><ul><li>Privacy </li></ul><ul><li>Do technology elites have the right to experiment and exploit the personal information of those who knows little about their information on the Web? </li></ul>
  29. 29. Summary <ul><li>Social Network sites allow people to create profiles and be virtually connected with family and friends. </li></ul><ul><li>Though many sites exists for business reasons, but they provide many value-added services and make our life more convenient. </li></ul><ul><li>FOAF and XFN are languages for describing profile and relationships on the Web </li></ul><ul><li>Facebook API, OpenSocial API and Social Graph API changed the way we use and think of social network sites. </li></ul>
  30. 30. Homework <ul><li>Post at least 1 blog on … </li></ul>