“Several studies, most notably by the Harvard Business School and Sysomos, have tried to analyze the user behaviour on microblogging services.[9][10] Several of these studies show that for services such as Twitter, there is a small group of active users contributing to most of the activity.[11] Sysomos’ Inside Twitter [10] survey, based on more than 11 million users, shows that 10% of Twitter users account for 86% of all activity.”

( Reading the above paragraph on Wikipedia, I just realized, the “1” in the 1-9-90 Rule when applied to Twitter, is really the People NOT on Twitter. The “9” are the People who are Linking TO or Tweeting ABOUT the Stuff found off-twitter written/blogged by that “1” Percent of Twitter “Users”. )

https://en.wikipedia.org/wiki/Microblogging