Understanding the social roles of the members a group can help to understand the social context of the group. We present a method of applying social network analysis to support the task of characterizing authors in Usenet newsgroups. We compute and visualize networks created by patterns of replies for each author in selected newsgroups and find that second-degree ego-centric networks give us clear distinctions between different types of authors and newsgroups. Results show that newsgroups vary in terms of the populations of participants and the roles that they play. Newsgroups can be characterized by populations that include question and answer newsgroups, conversational newsgroups, social support newsgroups, and flame newsgroups. This approach has applications for both researchers seeking to characterize different types of social cyberspaces as well as participants seeking to distinguish interaction partners and content authors.

This paper presents an analysis on the relationship between the communication behaviours of participants in newsgroups with their social structural position derived through network analysis over a one-month period. Nine newsgroups were evaluated which comprised of dissimilar user populations belonging to a range of genres which included; question and answer, conversational, social support and flame newsgroups. The aim of the research was to characterise differences between different author and newsgroup types.

The authors make an interesting observation of authors who showed up once to ask a question and if they receive a satisfactory answer, they would not be seen again. This was well illustrated in the question and answer newsgroup. I have personally encountered such users in online communities and have myself registered to new communities with the only intention of asking for help on a specific problem. Once I had solved my problem, I would not re-visit the community unless I required help on another domain related problem. I wonder if commitment to the community could be a factor I could incorporate in assessing user contributions in social software. Such a factor would need to evaluate the ratio of questions and answers a user has contributed, the total number of actual questions and answers as well as their overall usage frequency (i.e. do they log on weekly or once every few months?). It would be interesting if the authors conducted a similar experiment to other types of online communities such as forums, wikis and blogging communities to possibly identify different or new user types.

• Visualisation
• Newsgroups
• Interaction partners
• Egocentric social networks constructed through patterns of reply
• Netscan system
• JUNG
• Reciprocity of ties
• Power-law curve
• Degree of equality