(Originally posted by John Breslin on the IIA Blog.)

Social networking services (SNS) allow a user to create and maintain an online network of close friends or business associates for social and professional reasons. There has been an explosion in the number of online social networking services in the past four years, so much so that the terms YASN and YASNS (Yet Another Social Network[ing Service]) have become commonplace. But these sites do not usually work together and therefore require you to re-enter your profile and redefine your connections when you register for each new site. Let me start with an overview of SNSs.

You may be familiar with the Irish phrase “dúirt bean liom go ndúirt bean leí”, which occurs when someone tells someone something and they then tell you - the friend-of-a-friend effect - or the theory that anybody is connected to everybody else (on average) by no more than six degrees of separation. Where did this number of six degrees come from? A sociologist called Stanley Milgram conducted an experiment in the late 1960s. Random people from Nebraska and Kansas were told to send a letter (via intermediaries) to a stock broker in Boston. However, they could only give the letter to someone that they knew on a first-name basis. Amongst the letters that found their target, the average number of links was around 5.5 (rounded up to 6). Some other related ideas include the Erdös number (the number of links required to connect scholars to mathematician Paul Erdös, a prolific writer who co-authored over 1500 papers with more than 500 authors), and the Kevin Bacon game (the goal is to connect any actor to Kevin Bacon, by linking actors who have acted in the same movie). The six degrees idea is nicely summed up by this quote from a film called “Six Degrees of Separation” written by John Guare:

“I read somewhere that everybody on this planet is separated by only six other people. Six degrees of separation between us and everyone else on this planet. The President of the United States, a gondolier in Venice, just fill in the names. [...] It’s not just big names — it’s anyone. A native in a rain forest, a Tierra del Fuegan, an Eskimo. I am bound — you are bound — to everyone on this planet by a trail of six people.

You’ll often find that even though you follow one route to get in contact with a particular person, when you start talking to them there is another obvious connection between you and them that you didn’t know about previously. This is part of the small-world network theory, which says that most nodes in a network exhibiting small-world characteristics (such as a social network) can be reached from every other node by a small number of hops or steps.

Now we have websites acting as a social networking service. The idea behind such services is to make people’s real-world relationships explicitly defined online - whether they be close friends, professional colleagues or just people with common interests. Most SNSs allow you to surf from your list of friends to find friends-of-friends, or friends-of-friends-of-friends for various purposes. SNSs have become the new digital public places of Web 2.0 - just look at the huge takeup of sites such as MySpace, LinkedIn, Bebo and Facebook. Most SNSs allow content generation and sharing, and there is also a gradual transformation of SNSs into public e-markets - either through product promotions or targetted ads.

Social networking services usually offer the same basic functionalities: network of friends listings (showing a person’s “inner circle”), person surfing, private messaging, discussion forums or communities, events management, blogging, commenting (sometimes as endorsements on people’s profiles), and media uploading. Some motivations for SNSs include building friendships and relationships, arranging offline meetings, curiosity (nosiness!) about others, arranging business opportunities, or job hunting. People may want to meet with local professionals, create a network for parents, network for social (dating) purposes, get in touch with a venture capitalist, or find out if they can link to any famous people via their friends.

Before 2002, most people networked using services such as OneList, ICQ or eVite. The first big SNS in 2002 was Friendster; in 2003, LinkedIn (a SNS for professionals) and MySpace (target audience is 20-30 years) appeared; then in 2004 we had orkut (Google’s SNS) and Facebook (by a college student for college students); these were followed by Bebo (target audience is 10-20 years) in 2005. The graph on the right shows the growth of these sites over the past few years, according to Alexa. As of today, Bebo was ranked at #162 (even though it has just been around for about a year and half), Facebook at #34, orkut at #8, MySpace at #6, LinkedIn at #174, and Friendster at #36. I produced the top SNS table (in terms of membership) below from a list of social networking websites from Wikipedia; I could only describe it as indicative as some of the references for the figures are outdated.

There have been lots of venture capital and sales of SNSs as well. Friendster raised $13 million in its early years, Tribe.net got $6.3 million, LinkedIn $4.7 million, and Bebo $15 million. MySpace was sold to News Corporation for $580 million, Friends Reunited to ITV for £120 million, and Facebook received a purported $1 billion offer by Yahoo!; leaked papers suggest that there was actually $1.6 billion available for deal, but the founder wanted $2 (billion, that is).

Even in a small-sized SNS (the picture on the right is a part of the boards.ie friends network), there can be a lot of links available for analysis, and this data is usually meaningless when viewed as a whole, so one needs to apply some social network analysis (SNA) techniques. Apart from textbooks, there are many academic resources for social networks and SNA. For example, the tool Pajek can be used to drill down into various networks. A common method is to reduce the amount of relevant social network data by clustering. You could choose to cluster people by common friends, by shared interests, by geography, by tags, etc. In social network analysis, people are modelled as nodes or “actors”. Relationships (such as acquaintainceship, co-authorship, friendship, etc.) between actors are represented by lines or edges. This model allows analysis using existing tools from mathematical graph theory and mapping, with target domains such as movie actors, scientists and mathematicians (as already mentioned), sexual interaction, phone call patterns or terrorist activity. There are some nice tools for visualing these models, such as Vizster by Heer and Boyd, based on the Prefuse open-source toolkit. Others have combined SNA with Semantic Web technologies to determine social behaviour patterns, and MIT Media Lab are conducting mobile SNA research via their “reality mining” project.

With all such online interactions, people should limit the amount of personal information they put up (see my previous article on cyberstalking) as they are revealing more and more information on SNSs and other social software sites. There can be personal privacy issues, where sensitive information is revealed unknowingly. Depending on the signup agreements, advertisers and marketers can gain a better understanding from customer behavioural patterns by analysing masses of social network information, using “topic clouds” to show the overall picture (this may be good or bad from your point of view - maybe you want targetted ads showing you offers in areas you are interested in). On the security front, the NSA are using social network analysis technologies for homeland security, and there have been reports from the New Scientist of “automated intelligence profiling” from sites like MySpace based on potentially unreliable information.

So what does the future hold for SNS sites? It has been theorised that many sites only work where there is some “object-centered sociality” in networks, i.e. users are connected via a common object, e.g. their job, university, hobby, etc. In this way, it is probable that people’s SNS methods will move closer towards simulating their real-life social interaction, so that people will meet others through something they have in common, not by randomly approaching each other. In the future, we will no doubt see better interaction methods with friends à la Second Life.

But the main interest I see is in terms of distributed social networks and reusable profiles. There have been a lot of complaints about the walled gardens that are social network sites (and a recent balanced analysis from Danah Boyd). Some of the best SNSs out there would not exist without the walled garden approach, so it’s not all bad, but some flexibility would be nice. Users may have many identities on different social networks, where each identity was created from scratch. A resusable profile would allow a user to import their existing identity and connections (from their own homepage or from another site they are registered on), thereby forming a single global identity with different views (e.g. there is Videntity which works with OpenID and FOAF).

For those who are interested in setting up their own social network, I can suggest the following. First of all, you can try the open source AroundMe and Yogurt systems. Secondly, there are two books of general interest (i.e. not too scientific): “Linked” by Albert-Laszlo Barabasi and “Six Degrees” by Duncan J. Watts (one of the formalisers of the small-world network theory).

That’s all from me for the IIA Blog. I hope you’ve enjoyed my two week guest series of posts on Web 2.0, and I’ll be back to my own Cloudlands blog again tomorrow… Bye!