Define gender gap? Try Wikipedia's contributors list

In 10 short years, Wikipedia has accomplished some remarkable goals. More than 3.5 million articles in English? Done. More than 250 languages? Sure.

But another number has proved to be an intractable obstacle for the online encyclopedia: surveys suggest that less than 15 percent of its hundreds of thousands of contributors are women.

Sue Gardner, the executive director of the Wikimedia Foundation, the organization that runs Wikipedia, has set a goal to raise the share of female contributors from barely 13 percent to 25 percent by 2015. But she is running up against the traditions of the computer world and an obsessive fact-loving realm that is dominated by men and, some say, uncomfortable for women.