1. CHAPTERS 11 & 13 THE SOCIAL SEMANTIC WEB

2. THE NEED FOR SEMANTICS IN ONLINE COMMUNITIES A major limitation with online communities at present is the repeated requirement to register an account on each new site that you wish to post content on. Another issue is in relation to the content that a user creates across a variety of sites. At the moment, without some links between the various user accounts that a person owns, it is almost impossible to obtain a complete set of content items that a person has created on all the sites that they are registered on. When searching for information on a particular topic using a traditional search engine, one will often have to traverse quite a few sites to find a complete solution to a certain query. Finally, there is at present no way to create and view ‘distributed conversations’ across a number of community sites. Blogs use the trackback system to create links between blog posts, but there is no standard method of doing the same on message boards or other services.

3. SEMANTICALLY-INTERLINKED ONLINE COMMUNITIES (SIOC) The SIOC initiative is aimed at interlinking related online community content from platforms such as blogs, message boards, and other social websites, by providing a lightweight ontology to describe the structure of and activities in online communities, as well as providing a complete food chain for such data. So far, SIOC has been adopted in a framework of about 60 applications or modules2 ranging from exporters for major Social Web platforms to applications in neuromedicine research, and has been deployed on hundreds of sites.

4. THE SIOC ONTOLOGY

5. EXPERT FINDING IN ONLINE COMMUNITIES The process of finding the right expert for a given problem (e.g. matching people’s skills, interests, tasks or responsibilities) has long been of interest to computer scientists, and with renewed interest it is now being tackled in domains ranging from language modelling (Balog 2006) to the Semantic Web (through the ExpertFinder initiative).

6. FOAF FOR EXPERT FINDING In terms of definitions of expertise by an individual, the FOAF ontology has a number of properties of note. Firstly, the foaf:topic_interest property defines topics of interest to a person, and can be used directly to find those with an interest in a particular domain when it is represented by its URI (e.g. from DBpedia), while the foaf:interest property links to a foaf:Document representing this interest. Secondly, people can create foaf:publications or other foaf:Document(s) (via foaf:made / maker) which may have an associated foaf:topic or foaf:primaryTopic that can again be used to determine a person’s domains of interest. Thirdly, foaf:currentProject / pastProject gives some information on some ‘some collaborative or individual undertaking’ that a person may be involved in.

7. SIOC FOR EXPERT FINDING With respect to finding experts in an online community, the main SIOC properties of interest are sioc:topic and dc:subject. sioc:topic defines a category resource that a particular discussion post is related to by aggregating all the sioc:topic(s) that are associated with a particular user’s posts across a number of sites, a picture emerges as to where their topics of interest and related expertises lie. sioc:Forum(s) or sioc:Site(s) may also have associated sioc:topic(s), and again a user with an interest in a particular topic may be a sioc:subscriber_of a certain discussion channel.

8. CONNECTIONS BETWEEN COMMUNITY DESCRIPTION FORMATS

9. DISTRIBUTED CONVERSATIONS AND CHANNELS Using SIOC, various linkages are created between the aforementioned concepts, which allow new methods of accessing this linked data including: Virtual Forums. These may be a gathering of posts or threads which are distributed across discussion platforms, for example, where a user has found posts from a number of blogs that can be associated with a particular category of interest, or an agent identifies relevant posts across a certain timeframe. If a person wanted to create a virtual forum for all of their own posts, instead of going around to each of their favorite sites and linking to their posts from a page, another option would be to do it in reverse - when their post was created, they would link back to their own post aggregation resource. Distributed Conversations. Trackbacks are commonly used to link blog posts to previous posts on a related topic. By creating links in both directions, not only across blogs but across all types of internet discussions, conversations can be followed regardless of what point or URI fragment a browser enters at. Unified Communities. Apart from creating a web page with a number of relevant links to the blogs or forums or people involved in a particular community, there is no standard way to define what makes up an online community, unless one groups the people who are members of that community using FOAF orOPML16 (Outline Processor Markup Language). We allow one to simply define what objects are constituent parts of a community, or to say to what community an object belongs (using Dublin Core’s hasPart and isPartOf relationships): users, groups, forums, blogs, etc. Shared topics. We allow the definition of free form tags (usingthe dc:subject property), but also enable hierarchical or non-hierarchical topic definition of posts using sioc:topic when a topic is ambiguous or more information on a topic is required. One Person, Many Users Accounts. SIOC also aims to help with the issue of multiple identities by allowing users to define that they hold other accounts or that their accounts belong to a particular personal identity (via foaf:holdsAccountor sioc:account_of).

10. DISTRIBUTED CONVERSATIONS AND CHANNELS

11. SIOC APPLICATIONS

12. SIOC API S SIOC Export API for PHP. The SIOC API for PHP25 provides an easy way to manipulate SIOC data through PHP objects and methods, and renders the data into RDF/XML. The API creates and exports SIOC concepts about communities of authors (sioc:User and foaf:Person), the thread starters and replies they create (sioc:Post and sioc_t:Comment), and the structure of the website (sioc:Site and sioc:Forum). SIOC API for Java. A SIOC API for Java26 has been created, based on semweb4j. For each object in the SIOC ontology, this API generates classes with links between the objects realised as Java properties. SIOC API for Perl. Version 1.0 of a SIOC API for Perl27 has been released on CPAN, thanks to Jochen Lillich and Thomas Burg. RDFa on Rails. RDFa on Rails28 is a library of helper methods to help Ruby on Rails developers with producing RDFa data. SIOC terms are used to describe blog posts in this library.

13. TOWARDS THE SOCIAL SEMANTIC WEB There are two sides to what we achieve by adding semantics to current social together in a stronger, more meaningful way. First of all, we are allowing people to connect Social Web content together in a much stronger way. For example, let us take the case of someone writing a blog article talking their recent trip to New York. They may want to put in some information about New York into the article, such as where it is. At the moment, that person would have to go to the Wikipedia and look it up. However, on the Social Semantic Web, the DBpedia (providing structured information from the Wikipedia) can act a data source for the kind of information the person may want to augment their article with. They could write an article about New York and annotate it with certain information, but all the information would be hidden behind the blog post, and if someone else wanted to reuse it they could just drag the embedded information on New York into their own site or application.

14. COMMUNITY GUIDED SOCIAL SEMANTIC WEB

15. CROWD WISDOM The first category is publishers, who will add ontologies to get more traffic to their sites and will receive feedback on these ontologies to help with improving their content. Users are the next group, as they will ‘play games’ to create and improve resources, will provide feedback to get better search facilities, and will create (lightweight, simple) ontologies for personalization and for organizing their own community groups. The third group is developers, who will package knowledge for specialized applications (e.g. for vertical search). Finally, advertisers will want to create and upload ontologies to express all the things that should match their commercial offerings.

16. GRASSROOTS APPROACH There are many different vocabularies on the Semantic Web that could be used together but still remain disconnected, since most developers or metadata creators are either unsure about how they can be related to each other or have just not come across them (unless they find them using services such as SchemaWeb8 or SearchMonkey’s recommended vocabularies list). Microformats have been successful in bringing semantic metadata to the Web through their active MediaWiki-based community, IRC channel and mailing lists. The VoCamp10 series of vocabulary creation workshops aims to achieve this goal, by offering regular gatherings in different locations where people interested in creating lightweight vocabularies for the Semantic Web can meet and work towards this goal. Similar to BarCamp events, these workshops consist of informal sessions and the vocabularies to be created depend on the will of the participants.

17. THE VOCABULARY ONION

18. PRIVACY People are often unaware that many sites are making semantic forms of their profiles or content available which can be reused elsewhere. Tribe.net14 turned off their FOAF exports15 after a user complained that their profile was being copied for use elsewhere (the original developer team had moved on16 and the new developers were not familiar with the Semantic Web). Similar scenarios were encountered in the world of blogging, where people were surprised to find that content from RSS feeds on their personal sites was appearing on other aggregators or services

19. IDENTITY FRAGMENTATION For example, many people are careful to keep their personal life distinct from their professional life. However just as people may wish to keep separate identities for some purposes, it can also be beneficial to be able to connect these personas when desired. Identity Fragmentation implies a need for new ways to authenticate queries or carry out inferencing, by delivering data in different manners depending on, for instance, which social subgraph the person requesting the data belongs to (family, co-worker, etc.).

20. THE VISION OF A SOCIAL SEMANTIC WEB