A significant amount of data collected about Wikipedia has been coming out recently, especially from Internet monitoring firm Hitwise, revealing some interesting information about the project's readers and contributors.

The largest single data release came in conjunction with the Pew Research Center for the Pew Internet & American Life Project (all of the information in this article is limited to the United States). Pew and Hitwise prepared a report (PDF) released 24 April and focused entirely on Wikipedia, using information collected in February and March.

Overall, according to Pew's survey, 36% of adults have consulted Wikipedia, with an average of 8% doing so on any given day. Factors related to Wikipedia use included education, household income, and home broadband Internet access. Wikipedia use increased steadily according to income level, but ultimately education had the strongest effect. Half of those having a college degree said they used Wikipedia, the highest of any group, along with 46% of current students.

The report concluded that for most people seeking information online, convenience was a higher priority than increased accuracy. The easy availability of Wikipedia combined with traffic drawn from search engines helps explain the project's popularity.

Hitwise also came out with additional research, the results of which first began appearing a couple weeks ago at a Web 2.0 conference. Speaking at the conference, Hitwise researcher Bill Tancer gave some figures on the level of involvement at several participatory websites. He noted that the overwhelming majority of visits to sites such as YouTube and Flickr only involved passive consumption, not actually contributing to the site's content. They fell under the "90-9-1 Rule" identified by Jakob Nielsen, with less than 1% of visits involving actual uploads. By way of comparison, Wikipedia had a much higher participation rate, with 4.56% of visits being related to editing activity. (It should be noted, however, that YouTube or Flickr uploads imply earlier preparation of the content, while Wikipedia edits do not necessarily.)

This tidbit was included in a piece for Time magazine, also written by Tancer, that followed the Pew report. This article provided some interesting additional demographic data about Wikipedia. For example, Tancer said that the gender distribution of visitors was almost evenly divided male-female, but 60% of edits were by men. The imbalance among editors is actually mild in comparison with previous estimates, based on purely anecdotal guesswork, that contributors might be as much as 80-90% male.

Even more intriguing was the data on the age distribution of Wikipedia editors. Tancer wrote that "82% of those making edits to the site are 35 years old or older." This claim met with considerable skepticism among Wikipedia editors who thought the balance would be skewed more in favor of younger college students.

While it is difficult to identify the true reason without knowing more about the methodology, some possible explanations come to mind. One possibility is that like other monitoring firms, Hitwise faces challenges in tracking the younger crowd: individual activity may be hard to differentiate behind library or school computers, or incorrectly credited when high school or college-age students use a shared household computer belonging to their parents. However, Tancer did specifically point to a significant gap between visits, of which 45% came from people under 35, and edits, which he had coming mostly from the 35-and-over crowd.

Another factor to consider is that even if the population of editors seems relatively young — because this group has more free time to develop a well-known identity — it does not mean this age distribution is universal. Thus the large mass of unknown, often unregistered, editors might lean more toward those who are significantly older, with additional responsibilities in life and only a small amount of time to devote to Wikipedia. The real answers would require more data, and could be an interesting issue for further study.