The Pareto principle, more commonly known as the 80/20 rule, is the idea that roughly 80 percent of activity will be accounted for by 20 percent of the participants. Vilfredo Pareto’s initial observation at the start of the 20th century, that 80 percent of Italy’s land was owned by 20 percent of the population, has become a common rule of thumb in business, but does it hold up when tracking activity for the U.K.’s most popular social networks?

To see if it does, we equated activity with ‘time spent’ to reflect who is posting or consuming content. The U.K. audience to each site in January 2010 was divided into groups: ‘light’ visitors – those spending no more than five minutes on the site during the month; ‘medium’ visitors – those spending between five minutes and 60 minutes: ‘heavy’ visitors – those spending more than 60 minutes. It’s worth noting that equating activity to ‘pages viewed’ instead of ‘time spent’ produced similar results to the graphs below.

Grouping Twitter’s U.K. audience in this way reveals ‘light’ users account for 67 percent of the site’s audience and average less than 2 minutes on the site during the month. The ‘medium’ users account for 26 percent of the audience, averaging over 22 minutes. The ‘heavy’ users’ account for 7 percent of the audience but average almost 6 hours and 17 minutes.

Pareto would suggest that 20 percent of the visitors to a site would account for 80 percent of the total time spent on that site. However, for Twitter in the U.K., almost 80 percent of the time spent on the site is accounted for by the 7 percent of ‘heavy’ visitors. Conversely, 93 percent of the people who visit Twitter account for just 20 percent of the content posted and consumed.

Twitter’s activity metrics are not unusual when compared with other social networks. Three percent of MySpace’s visitors account for 63 percent of total time spent on the site; 14 percent of Bebo’s visitors account for 87 percent of total time. For LinkedIn, 5 percent of visitors account for half the total time. Half of Facebook’s U.K. audience (52 percent) account for almost all (98 percent) of the time spent on the site. This is because during the month of January, Facebook’s ‘heavy’ visitors averaged 14 hours 20 minutes, their ‘medium’ users (32 percent of the audience) averaged 30 minutes while their ‘light’ visitors (16 percent) averaged less than 2 minutes. Original Source: http://blog.nielsen.com by Alex Burmaster, Communications Director, UK & EMEA, Nielsen’s online division discusses