Anders Wennersten, 23/11/2013 08:49:
I have assumed it is an effect of Google starting to
show an extract
from Wikipedia on the page where they show hit results.
Assumptions are dangerous. The feature was apprently enabled on
2012-12-04 for Spanish, French, German, Portuguese, Japanese, Russian
and Italian; all those languages show a decrease in page views on that
month (except Russian whose trend is constant though)...
http://stats.wikimedia.org/EN/TablesPageViewsMonthlyCombined.htm
Nemo