I don't always follow Twitter as closely as I probably should - but then, I do find that it takes an inordinate amount of time out of my day if I really look closely and frequently to see what my friends are posting. Twitter's growth has been phenomenal, by all the numbers - but who is really out there tweeting?
Now we have some useful numbers, from the Pew Research Center's Internet & American Life Project, that give us a clearer pictur about who's tweeting. Pew says it's their first-ever Twitter-only study. It finds that , about 8% of American Internet users are also Twitter users. Among the heavy users are African-Americans and Latinos, younger (18-29) users and urban residents. Another interesting figure: about a quarter of all Twitter users say they check in more than once a day to catch up on posts from other users - but about one in five say they never check in to see what others are saying.
You'll find a good summary from Jack Loechner at MediaPost's Research Brief blog. It suggest an enormous growth potential still for Twitter - though it still doesn't really answer my question about how I can keep up with all those I'm following and still have time for a life...