I’ve copied the latest Wikipedia geo stats below. Its interesting that there is not a direct correlation between the population of a country and how active that country is on Wikipedia. Other variables to account: weather, literacy, availability of computers, lack of nightlife (kidding on the last one)

I just sat through a Jimmy Wales presentation at AdTech, and he presented the following data for the most popular languages on Wikipedia. Please note that this data is valid for the current date, April 21, 2009

English - 2.8 million articles

German, French, Dutch, Japanese, Italian - 500K + articles

Spanish, Russian, Swedish, Portuguese - 250K + articles

Chinese - nearly 250K articles

Wikipedia was banned in China for 3 years, which accounts for the lack of articles in Chinese.

I think this data could be particularly useful when prioritizing geographies for building communities as well as for building translation services for existing communities.