For those of you that are interested in this subject, here's a report
that has Wikipedia as the 4th-fastest-growing website in the US for the
month of September, in terms of unique visitors.
http://biz.yahoo.com/prnews/041015/cgf040_1.html
A lot of the growth is driven by students doing school research;
Britannica ranked as the 9th-fastest-growing for the same time period.
We're growing faster than they are, both in percentage terms and in raw
numbers, but they're still ahead overall.
--Michael Snow