Wikipedia, the massive so-called free encyclopedia of the social Web supported by the nonprofit Wikimedia Foundation Inc., surpassed an important milestone for mobile Web traffic, as the site reported Friday that it had 3 billion mobile page views in January.

“This means 14.5 percent of Wikipedia page views now are to the mobile site, up from 9.9 percent a year ago,” Amit Kapoor, Wikimedia’s senior manager of mobile partnerships, said in a blog post announcing the news. “Our target in the 2012-13 annual plan is to hit 4 billion monthly mobile page views by the end of the fiscal year (June 2013).”

While 3 billion monthly page views -- on mobile devices, no less -- is impressive in its own right, the new figure also represents a meteoric rise for Wikipedia’s mobile traffic during the past two years alone. In December 2010, Wikipedia was receiving just 4.1 percent of its monthly traffic, or 500 million page views, via mobile devices.

“Mobile page views rose over 75 percent in 2012, while desktop traffic grew at just under 20 percent,” Kapoor said. “It is clear that much of Wikipedia’s growth is happening on mobile.”

As a content company, Wikimedia is aware of the same trend that any other digital publisher paying close attention to the smartphone and tablet markets has noticed: Mobile platforms give consumers more points of entry to a company’s content or service, which can help build a user base beyond its desktop-friendly audience. Someday, the mobile market may even surpass the personal-computer market entirely.

Kapoor wrote: “We know that two things contribute significantly to this [growth in mobile consumption]: 1) With mobile Internet, readers have new reasons to look things up on Wikipedia, be it either related to context and location or convenience and availability; 2) Many readers in developing countries, specifically where there is limited broadband penetration, are using mobile devices as their first or only means to access the Internet.”

Wikipedia’s growth not only across delivery platforms but also in countries around the world has clearly been monumental, but it has led to monumental challenges, as well.

Along this line, University of Minnesota computer-science researchers produced a study -- “The Rise and Decline of an Open Collaboration System: How Wikipedia’s Reaction to Popularity Is Causing Its Decline” -- that was recently published online by the journal American Behavioral Scientist.

The researchers found that while the number of Wikipedia’s readers has been massively rising since 2005, its number of active contributors has been steadily falling since 2007.

As Wikipedia continues to expand into developing countries, this phenomenon raises a question of how democratic and inclusive the self-described “collaboratively edited, multilingual, free Internet encyclopedia” can and will be.

For starters, Sue Gardner, the Wikimedia Foundation executive director, acknowledged in a recent Los Angeles Times op-ed piece, “Nine of 10 Wikipedians [meaning its contributors] are male.”

"Open collaboration systems, such as Wikipedia, need to maintain a pool of volunteer contributors to remain relevant," Aaron Halfaker, a computer-science doctoral student at the University of Minnesota’s College of Science and Engineering who served as the study’s lead author, said in a statement. A “sharp decline in the retention of newcomers” could mean that, even as the site grows, the community that supports it -- and the kind of expertise that community provides -- might not grow along with it.

“Wikipedia has changed from the encyclopedia that anyone can edit to the encyclopedia that anyone who understands the norms, socializes himself or herself, dodges the impersonal wall of semi-automated rejection, and still wants to voluntarily contribute his or her time and energy can edit,” Halfaker said.

Questions of Wikipedia’s culture and ethics aside, its shrinking contributor base poses a fundamental challenge for its growth potential in developing countries.

“Wikipedia is actually available in 286 languages,” Gardner said in an interview this week with American Public Media Marketplace’s Kai Ryssdal. “It’s pretty much available in every language that’s spoken by a reasonably large number of people in the world.”

However, Gardner admitted that “English is the most edited” language on the site by far, and “people in developing countries tend to be disproportionately editors.”

Nonetheless, Gardner said, “[W]e aspire to broaden out the diversity of people who are contributing to Wikipedia, so that it will be better, and richer, and stronger, and smarter, and more useful for people.”

Broadening that diversity may be key for Wikipedia, assuming it wants to reach 4 billion mobile page views as quickly as it says it does.

RELATED STORIES