1. Notes from J. G. Breslin, A. Passant, and S. Decker The Social Semantic Web 3.2.8 Folksonomies Contributed content on social websites may be tagged with a keyword by the content creator or sometimes by community members  A tag is a keyword annotation that acts like a subject or category for the associated content Folksonomies are constructed from these tags:

2. 3.3 Object-centered sociality Social networks are designed to help us work together on common activities But many online social networking services (SNSs) lack such common objectives  Social networking sites are becoming meaningless.  And SNSs don’t usually work together It’s theorized that the longevity of social websites is proportional to the ‘object-centered sociality’ occurring in these networks  I.e. the degree to which people are connecting via items of interest Some advocate augmented social networks  Citizens self-organize into communities around shared interests

3. Adding annotations to items in social networks is useful for finding interesting items and people with similar interests  Topic tags, geographical pinpointing, etc. People’s SNS methods will probably continue to move closer towards simulating their real-life social interaction  Meet others via something in common  Eventually more realistic interaction methods with friends Online connections become intertwined with their real-world interests Multiplayer online gaming has had groups (‘clans’) of people working towards common purposes for over a decade  Virtual worlds (e.g., Second Life) have begun to provide a user experience more faithful to reality Networks of friends interact in more realistic ways

4. 10 Social networks 10.1 Overview of social networks Anybody is connected to everybody else (on ave.) by  6 degrees of separation. (sociologist Stanley Milgram)  Cf. the Erdős number, the Kevin Bacon game Often, one route is followed to get in contact with a particular person  But, after talking to them, there’s another obvious (but previously unknown) connection  Cf. the small-world network theory (Watts and Strogatz)

5. Even in a small SNS, there can be a lot of links  This data is usually meaningless when viewed as a whole  Usually apply social network analysis (SNA) techniques Can reduce the amount of relevant data by clustering  People modelled as nodes or  Relationships (co-authorship, friendship, etc.) as edges

6. 10.2 Online social networking services The idea behind online SNSs is to make people’s real-world relationships explicitly defined online Enable communities of like-minded people to group together  Talk about items and interests that they can’t talk about as effectively or regularly via meetups, phone conversations, e-mail Also useful for networks of geographically-disconnected friends Valuable for getting in touch with someone whose advice or skills you need, through a friend-of-a-friend or … Social networks are sometimes used for viral marketing A key feature of these sites is community-contributed content that can be commented upon by others. Many SNS are also opening up to web crawlers  Make users’ profiles and content searchable and accessible without being logged onto the site

7. 10.3 Some psychology behind SNS usage Few users realize the very public nature of content on these SNSs Few grasp the persistent nature of information on the Web Due to the social norms in SNS-based communities (the perceived closed nature of the community), individuals may act in a more ego-centric manner than they would in other situations (‘everyone is doing it’) Virtual reputation is also an obsession with SNS users A ritualistic element to SNSs  People enter their daily thoughts on a blog linked to their profile and check in for comments regularly

8. 10.4 Niche social networks It’s the fine-grained and targeted communities (e.g., CafeMom, BOOMj and PEERtrainer) that are experiencing growth  Cf. object-centered sociality above Suppose the rise in universal SNSs (e.g., Facebook, MySpace) is mirrored by an explosion in the growth of niche SNSs  This would accelerate the demand for semantic-type applications  Let people travel seamlessly through various social networking services, finding objects related to their interests

9. 10.5 Addressing some limitations of social networks Most SNSs usually don’t work together  Re-enter your profile and redefine your social connections when you register for each new site Standard sign-on systems like OpenID and profile representation mechanisms like FOAF let us define our identity and reuse it Semantic Web vocabularies like FOAF and microformats like hCard and XFN (XHTML Friends Network) can serve as platforms for  linking or reusing the diverse info about a person from heterogeneous social networking sites  performing operations on such reusable and linked data ‘Social network portability’: the ability to reuse one’s own profile across various social networking sites and applications Beginning to see distributed social networking platforms where social connections can be formed across sites

10. Recent developments let people collect and manage their identities across various SNSs (PeopleAggregator, 30boxes [calendaring web application], etc.) Solutions like OpenID let people have a single sign-on to any of the SNSs they belong to  OpenID is an open standard that lets users be authenticated by certain co-operating sites using a 3 rd party service The DiSo (Distributed Social Networking applications) project aims to implement open-source distributed social networks  Building Wordpress plugins that implement or build on microformats like XFN, hCard, XOXO (wp-contactlist, wp-profiles) OpenID (wp-contactlist, wp-openid-server) OAuth (lets a third-party application get limited access to an HTTP service)

11. A smaller set of standard, reusable contact formats could make such services more widespread  The Google Social Graph API can enable this Lets applications reuse social graph info extracted from sources all over the Web and represented using the open formats XFN and FOAF

12. 10.6 Friend-of-a-Friend (FOAF) Semantic Web technologies allow a more expressive description of a social network  Use heterogeneous nodes and links denoting different types of objects and relationships  Lets us express a model for an object-centered network  Content and other items of interest are described along with people in a decentralized way Anyone can create their own FOAF file describing themselves and their social network using tools such as  FOAF-a-matic (http://www.ldodds.com/foaf/foaf-a-matic) orhttp://www.ldodds.com/foaf/foaf-a-matic  FOAF Builder from QDOS FOAF data can be easily produced from social software systems that feature some user profiles and friends lists

13. Now some examples of tasks that can be done using social network data expressed in FOAF that would be difficult otherwise 10.6.1 Consolidation of people objects Merging identifiers of equivalent instances occurring across different sources Object consolidation (‘smushing’) can be done for instances that share the same value for inverse functional properties (IFPs)

14. 10.6.2 Aggregating a person’s web contributions Retrieve content a person has contributed to various sources on the Web, e.g., all documents, images, chat events, etc.  Hard with a normal search engine  People may share their name with other people  May use different account names on different sites This query is based on a precise URI—won’t retrieve documents created by the same user while using another URI One option is to define owl:sameAs statements between this URI and others for the same person Another is to run the query not based on the URI, but rather based on an IFP

15. 10.6.3 Inferring relationships from aggregated data A sample SPARQL query for extracting the social network formed by explicit foaf:know s relationships PREFIX foaf: SELECT DISTINCT ?s ?o WHERE { ?s a foaf:Person. ?o a foaf:Person. ?s foaf:knows ?o. } Also many implicit social connections on the Web  Links between people may be inferred due to links through some common objects—e.g., people appearing in the same pictures, tagging the same documents, or replying to each other’s blog posts

16. 10.7 hCard and XFN Like FOAF, hCard can be used to define properties relating to people, including ‘bday’ (birth date), ‘email’, ‘nickname’, and ‘photo’  These properties are embedded within XHTML attributes  Incorporates the Geo microformat to identify the coordinates for a location or ‘adr’ (address) described in an hCard XFN (XHTML Friends Network) is another social network-oriented microformat  Developed in 2003, just before the creation of the microformats community  Lets us define relationships between people—e.g., ‘friend’, ‘neighbor’, ‘parent’, ‘met’

17.  Supported through the WordPress blogging platform When adding a new blogroll link, use a form with checkboxes to specify additional metadata regarding the relationship between the blog owner and the person linked to The different types of person-to-person relationships available in XFN allow richer descriptions of social networks than FOAF (has only ‘knows’)  But FOAF can be extended with richer relationship types via the XFN in RDF vocabulary or the Relationship vocabulary

18. 10.8 The Social Graph API and OpenSocial 10.8.1 The Social Graph API The social graph and ‘social network portability’ are mainly about bringing your social network connections from one site to another  Being on Facebook, you could move to LinkedIn and bring your profile and connections with you The global social graph is composed of all the social network connections that are distributed across a multitude of sites

19. Google’s Social Graph API (discontinued in 2012) is a step in this direction  Returns web addresses of public pages and publicly-declared connections between them This data is got from FOAF and XFN info embedded in other crawled pages Combined with specialist knowledge about the structure of certain large social websites Previous FOAF aggregator efforts (Plink, FoaFSpace) didn’t achieve critical mass

20. 10.8.2 OpenSocial The OpenSocial API is an initiative from Google that enables ‘gadget’ portability  Social applications can be deployed across a variety of social networking sites Google, Yahoo! and MySpace also formed the OpenSocial Foundation (http://opensocial.org/)http://opensocial.org/  A non-profit entity to support such social application portability  The most mature standards-based component model for cloud based social apps

21. 10.9 The Facebook Platform Some of the Facebook Platform technologies available for developers  FBML (Facebook Markup Language) A form of HTML to customize the look-and-feel of one’s applications  FQL (Facebook Query Language Lets us easily query Facebook data from our applications in an SQL-like syntax  The Facebook API lets Facebook social data be integrated into applications, e.g. data on friends, groups or events  FBJS (Facebook JavaScript) Lets us ‘sandbox’ JavaScript in their FBML code—the JavaScript of one application hasn’t access to anything outside of its own scope

22. All of these have been licensed in more generic forms as  SNML (Social Network Markup Language),  SNQL (Social Network Query Language),  SNAPI (Social Network API), and  SNJS (Social Network JavaScript) to the Bebo SNS (used to be popular in the UK) Facebook Connect lets us connect our Facebook identity, friends and privacy to any site  Lets 3 rd parties implement and offer features from the Facebook Platform on non-Facebook sites OWF (Open Web Foundation, established 2008) provides a venue for Google and Facebook to resolve differences between their Open-Social and Facebook platforms  And work on a standard way for their users to interact with each other

23. The APIs for accessing Facebook data have specific terms of use which restrict the caching of their data OpenLink developed an RDFizer middleware layer that talks to FQL  Converts the requested Facebook profiles or associated data (e.g. photo albums) returned in XML form into semantic linked data on the fly, without caching Facebook FOAF Generator returns FOAF data for a user who has authenticated with the service

24. 10.10 Some social networking initiatives from the W3C W3C Social Web Incubator Group (April 2009-Dec. 2010) http://www.w3.org/2005/Incubator/socialweb/ See the final report “A Standards-based, Open and Privacy-aware Social Web” http://www.w3.org/2005/Incubator/socialweb/XGR-socialweb-20101206/  The Social Web should allow people to create networks of relationships across the entire Web, while giving them the ability to control their own privacy and data  The standards enabling this should be open  The report presents a framework for understanding the Social Web and the relevant standards in the report  Proposes a strategy for making the Social Web a "first-class citizen" of the Web

25. 10.11 A social networking stack Rather than building a separate social networking layer into tools, info space and application architects need to fold it into various technology stacks The Nepomuk project (Chap. 13) does this for the desktop But there’s evolution toward ubiquitous computing and the ‘Internet of things’  Will deliver much more info  The Internet infrastructure itself might need to be augmented to include a social networking infrastructure Keep users from drowning in an ocean of unconnected and meaningless info

26. A social networking stack needs to take into account a person’s relevant objects of interest  Provide some limited data portability The actions and interactions of a person with other users and objects (exhibiting relevant properties) in existing systems can be used to create new user or group connections when a person registers for a new social networking site or application Instead of a fragmented view of one’s network in each application, the social networking stack would let a user use all of their person-to-person connections in any application Making social networking a shared component across various desktop and Web applications

27. The cross-application social networking stack requires several layers 1. Personal authentication and authorization layer  Using a single sign-on mechanism (e.g. OpenID, Sxip) 2. Social network access layer  Using the social networking contacts created by an individual across various platforms E.g., by collecting FOAF ‘knows’ relationships from multiple sites  Access control is required: social connections aren’t always bi- directional 3. Content object access layer  Collect a person’s relevant content objects  Verify that they’re allowed to reuse data and metadata from these objects in the current application  For reputation purposes, verify that these items are in fact created by the authenticated individual on whatever sites they reference