Social media is exploding! In a good way that is, not in a dramatic, cataclysmic manner. According to Bob Brisco, CEO of Internet Brands, more than half of all internet visits (in the US) are to user-generated content or social media sites – what we will term the Social Web. We’ve seen the rise of sites like Facebook (on which more time is spent than Google, Yahoo! and AOL combined) and Twitter (which today announced 100 million active users per month), and the fall of services like Bebo and Myspace.

Through social media sites, people are connected to others through the social objects that they create and share and co-participate in. These may be discussions, bookmarks, microblog posts or multimedia items, and can be on topics ranging from pets to music to holidays in Spain (or even about all three!).

Unfortunately, many social media sites act as data silos wherein the content that people are creating is locked. There are many isolated communities of users and their data. There’s a real need to connect these ‘islands’, allowing users to have mobility from one service to another and to be able to bring their data with them (profiles, photos, posts, etc.).

So on the one hand, we have the Social Web, and on the other hand, we have an effort called the Semantic Web. What’s that? Well, we as people can look at a web page and we can instantly recognise different facts. “Technology Voice is an online publisher.” “They have an office in Galway.” “Galway is a city in Ireland.” But for a computer, it’s a lot harder for it to extract these facts and to link them together. That’s what the Semantic Web does – it creates computer-understandable statements or facts that can be linked together across different websites. Then computers can use these linked facts to help us find information, to carry out tasks, to reduce the time spent piecing information together manually.

We can also do the same thing for the Social Web, so that the things that occur on these sites could be made understandable to computers (using semantics). “John is a user of boards.ie.” “John wrote this discussion post.” “This post is on the topic of Television.” “Mike replied to John’s post.”

The Social Semantic Web is the coming together of the Social Web and the Semantic Web. The Social Web is one evolution of the Web where we have moved from individuals posting information-type web pages to multiple people interacting on each page. In parallel, we’ve seen efforts to add more semantics to web pages, things like microformats and microdata, Google Rich Snippets and schema.org, and RDF, a Semantic Web standard from the W3C. This allows us to move from pages that are purely syntactic (e.g. defining styles for how to display text, headings, etc.) to semantic (describing the things mentioned in a web page).

Why should this marriage happen? It’s a two-way street: the Semantic Web can help the Social Web and vice versa. We can use the Semantic Web to describe people, content objects and the connections that bind them all together so that social sites can interoperate via semantics. In the other direction, object-centered social websites can serve as rich social data sources for the Semantic Web, which has often suffered from the so-called chicken-and-egg problem (no cool applications without data; no data without cool applications). People are creating semantically-rich information through their everyday interactions with social websites: tagging objects, replying to posts, making friend connections, retweeting, etc.

As Tim Berners-Lee, one of the creators of the Web, said in 2006: “I think we could have both Semantic Web technology supporting online communities, but at the same time online communities can also support Semantic Web data by being the sources of people voluntarily connecting things together.”

On the Social Semantic Web, there are a number of common vocabularies (sets of terms) that can be used to represent people, documents, social websites, etc. The first is called FOAF, or Friend-of-a-Friend. It is used to describe people and the relationships that exist between them – basically to provide a machine-readable version of a person’s identity and personal profile along with their social networks. FOAF data is produced from a variety of sites including LiveJournal, Identi.ca and hi5. You can create a distributed identity using FOAF: bringing together separate networks from various services, and integrating them into a single whole (if so desired).

Another vocabulary is SIOC (pronounced ‘shock’), developed by the author at DERI, NUI Galway and others. SIOC can be used to represent content (posts, comments, topics, etc.) on the Social Web for integration across a variety of platforms, and has been adopted in over a hundred frameworks including Drupal 7, Yahoo! SearchMonkey and the Newsweek website. By connecting content across different social websites, SIOC aims to enable new types of connections such as distributed conversations, virtual forums, unified communities, etc.

One common application for semantically-enhanced social content is in the search domain. With machine-readable versions of author names, number of replies, etc. for things like blog posts and forum discussions, this information can be used to enhance search results and add context to a result (showing something like “by John Breslin (32 Comments)”).

There are some other vocabularies like Meaning of a Tag and the Online Presence Ontology that, together with FOAF and SIOC, can be used to form a vocabulary stack of reusable and combinable terms for the Social Semantic Web. This stack is used in applications such as SMOB, a distributed semantic microblogging architecture developed by Alex Passant that allows users to own their own microblogging hub and to augment their posts with semantic hashtags that link to shared concepts (e.g. pages on the Wikipedia).

While the vision of a Social Semantic Web may not totally infiltrate the Social Web we use today, we can at least see some aspects of it being realised through efforts like the Facebook Open Graph Protocol and Twitter Annotations, and new services like Bottlenose. With systems like Drupal 7 now producing social semantic data out of the box, Manu Sporny estimates that there will be hundreds of thousands of these Drupal deployments within the next two years. It will be exciting to see what cool applications people will build on top of this data.

I am co-author of the book “The Social Semantic Web” with Alex Passant and Stefan Decker.