The past decade has brought a quiet revolution in social interaction caused by new technology. Mobile phones, e-mail and Google have combined to make us - and information about us - more accessible. Even without technologies that pose a more direct threat to privacy, from closed-circuit television cameras to internet cookies, everyday life has become more transparent. There are big personal and social benefits, but also side-effects: a loss of both privacy and the sense of privacy, and the risk of distraction that comes from being permanently available.

The latest wave of internet technology is shaping up to take this much further. Online social networking, for instance, is a habit that is spreading quickly. Two in five MySpace members are over the age of 35, and Facebook has nearly doubled in the US since reaching beyond its original student audience. Add in blogs and photo-sharing sites such as Flickr, and it seems that large numbers of people are discovering the joys of living their life in public, ready to sound off about what they are doing or thinking, or to share their friends with the social promiscuity of a teenager.