In the U.S a minority of twitter adult users produce a significant majority of tweets according to a recent Pew Research Center study. The article refers to Twitter users who tweet relatively infrequently as 'lurkers'.
1) Roughly half of U.S. adults who use Twitter (49%) post fewer than five tweets per month.
2) Lurkers report visiting Twitter’s site less frequently than more active tweeters.
3) Twitter lurkers are more likely to use the platform to hear other points of view than more frequent tweeters.
4) Lurkers follow – and are followed by – fewer accounts than more frequent tweeters.
5) Replies make up the largest share of lurkers’ tweets.