_Popularidad. Twitterratio. Twitter is Not Your Average Social Network. A study conducted by Harvard Business Review reveals that most Twitter users don't actually use the service much, or even at all.
In fact, 10% of active users are responsible for over 90% of all Tweets. According to the research, conducted on a random sample of about 300,000 Twitter users in May 2009, 25% of Twitter users don't tweet at all, while 50% of users tweet less than once every 74 hours. Active users, on the other hand, tweet a lot, which makes Twitter a lot more like Wikipedia than an average social network (see graph below, courtesy of HBR). Although this may sound strange at first, Twitter really is more like Wikipedia than, say, Facebook.
The 1% Rule: Charting citizen participation: Church of the Customer Blog.