Athens.
The next speaker at WebSci '09 is Kieran O'Hara, who begins by noting the perception of an increase in the activity of extremist groups on the Web, but with very little clear actual evidence supporting that perception. (Extremism is defined here as living in great tension within an embedding society.) How do extreme ideas - for example of a religious kind - spread on the Web?
One approach to this is to view this - with David Hume - as a marketplace of religious ideas, in which the most extreme are the most visible. But against this, Adam Smith suggests that there is also a drive to the centre in the contest of religious ideas, with the aim to attract a larger number of followers. There may be, in fact, a church/sect cycle, and Kieran points to the Mormons as a former sect which has become an established church, while new more extreme splinter groups have also hived off from this church in recent time. Religious moderation means a lower cost of participation for church members, while extremism means higher costs, but also greater cohesion and contribution from the smaller number of committed supporters.