Maybe not news, considering our traffic rankings.... but this is one of the
first "real" studies of Wikipedia use I've seen, conducted by the
prestigious Pew Internet project and released in April 2007 in a "data
memo".
http://www.pewinternet.org/pdfs/PIP_Wikipedia07.pdf
The first few paragraphs:
" More than a third of American adult internet users (36%) consult the
citizen-generated online encyclopedia Wikipedia, according to a new
nationwide survey by the Pew Internet & American Life Project. And on a
typical day in the winter of 2007, 8% of online Americans consulted
Wikipedia.
There has been ongoing controversy about the reliability of articles on
Wikipedia. Still, the Pew Internet Project survey shows that Wikipedia is
far more popular among the well-educated than it is among those with lower
levels of education. For instance, 50% of those with at least a college
degree consult the site, compared with 22% of those with a high school
diploma.
And 46% of those age 18 and older who are current full- or part-time
students have used Wikipedia, compared with 36% of the overall internet
population.
In addition, young adults and broadband users have been among those who are
earlier adopters of Wikipedia. While 44% of those ages 18-29 use Wikipedia
to look for information, just 29% of users age 50 and older consult the
site. In a similar split, 42% of home broadband users look for information
on Wikipedia, while just 26% of home dial-up users do so."