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."