The Pew Research Center's Internet & American Life Project completed a study in Nov. 2010 about who uses Twitter. With the zeal that every entity from US Senators to mass media companies promote their presence on Twitter, one may get the impression that everybody is using it. You may be surprise by some of the findings from this study. Here are some highlights:

In this survey, 8% of online adults  said they do use Twitter with 2% doing so on a typical day. This survey also showed that 74% of American adults are internet users,  meaning that the Twitter cohort amounts to 6% of the entire adult population. Some of the groups who are notable for their relatively high levels of Twitter use include:  
-Young  adults  - Internet users ages 18-­‐29 are significantly more likely to use Twitter than older  adults.  
-African-­‐Americans  and  Latinos  - Minority  internet  users  are  more  than  twice  as  likely to use Twitter as are white internet users.  
-Urbanites  -  Urban residents are roughly twice as  ikely to use Twitter as rural dwellers.

One-­‐quarter of Twitter users check in multiple times per day for tweet  from others, while one in five never check for new material of the site

Check out the complete study here:

http://www.pewinternet.org/Reports/2010/Twitter-Update-2010/Findings.asp...

(study is available as a free download, which includes the methodlogy for those skeptics among us.)

Jonathan