There are signs that social notworking is about to go the same way as the hoola-hoop, the walkman, the dodo and the iPod. According to a recent statistical analysis by RJ Metrics, while networking sites such as Twitter are still growing at lightning speed, the sign-up rate for new users has slowed.

Meanwhile Websites helping people purge their social network sites have gained popularity. Twitter is still adding 6.2 million new users a month, that's down 20 per cent from its peak last summer. It's well worth noting that less than 17 per cent of Twitter users are actively using it.

RJ Metrics said that while Twitter now has 75 million users, many of them are inactive, a quarter of twits have no followers and 40 per cent of those who signed up for Twitter have yet to send a single message. The average twit has 27 friends.

RJ Metrics said that 80 per cent of all Twitter users have tweeted fewer than 10 times.