Anti-Social Networks

"This is consistent with previous research on online communication, says Scott Caplan of the University of Delaware in Newark, who suspects that heavy users of sites such as Digg and Twitter may have similar characteristics. 'People who prefer online social behaviour tend to have higher levels of social anxiety and lower social skills,' he says."

Peter Aldhous in New Scientist explores research into who contributes to "community-curated" websites like Wikipedia..