A well known rule of thumb in business is the so-called Pareto principle (or the 80/20 rule) that 20% of participants will account for 80% of the activity. Metrics firm Nielsen decided to test out if the same applies to Twitter - do 20% of tweeple account for 80% of what takes place on Twitter.
The answer is no. At least in the UK, an even smaller number - 7% - account for 79% of Twitter activity.
Nielsen found that 'light' users (less than 2 minutes per month, actually broken across 30 days that is pretty much zero) account for 67% of the audience, medium users (22 mins per month, so still less than a minute a day) account for 26%, while heavy users (1hr+ a month) account for 7% of UK tweeple.
Nielsen's stats confirm previous ones by Canadian research firm Sysomos, which showed that there is a group of 5% of Twitter power users who are responsible for 75% of Twitter activity.
Similarly, in January, RJ Metrics produced a report saying that only 17% of Twitter accounts had sent a single tweet over the month, which would put Twitter's 'real' user base at around 10-15 million worldwide (with perhaps 700-900k in the UK) as opposed to the 75 million registered users.
Again, the fact that there are probably less than a million people in the UK making habitual use of Twitter shouldn't matter. News often breaks on Twitter and, due to the large proportion of bloggers and journalists that listen in on the network, moves elsewhere.
As the founder of spoof political website mydavidcameron.com (lampooning ads featuring the UK Conservative Party leader) found, chatter about his website started on Twitter and then quickly moved on from there to Facebook and finally to the media at large.
Finally, it's also worth bearing in mind Nielsen's observations that other networks similarly have a core of power users who dominate. Three percent (3%) of MySpace visitors account for 63% of time spent on the site while 5% of LinkedIn visitors account for 50% of LinkedIn activity. A challenge for marketers targeting those networks is obviously to zero in on, and find out who those three or five percent are.
Linking in with its role as a network, which according to Reuters is rapidly gaining 'tech lock in', Facebook however has a higher participation rate - 52% of users account for almost everything (98%) that goes on.