Starting editing wars (Image: Frederic Sierakowski / Rex Features)

Wikipedia has rapidly become one of the most used reference sources in the world, but a new study shows that the website’s explosive growth is tailing off and also suggests the community-created encyclopaedia has become less welcoming to new contributors.

Ed Chi and colleagues at the Palo Alto Research Center in California warn that the changes could compromise the encyclopaedia’s quality in the long term.

“It’s easy to say that Wikipedia will always be here,” says Chi, a computer scientist. “This research shows that is not a given.”


Launched in 2001, the English language Wikipedia grew rapidly to its current size of almost 3 million articles. However, when the Palo Alto team analysed a downloaded version of the encyclopaedia they found its growth has peaked.

The number of articles added per month flattened out at 60,000 in 2006 and has since declined by around a third. They also found that the number of edits made every month and the number of active editors both stopped growing the following year, flattening out at around 5.5 million and 750,000 respectively.

Editor wars

The balance of power within the people who contribute to Wikipedia also appears to have shifted – away from casual contributors who make infrequent changes, toward more active and established contributors. Chi says the trend could shut out new users.

“Occasional” editors, those who make just a single edit a month, have 25 per cent of their changes erased, or reverted, by other editors, a proportion that in 2003 was 10 per cent. The revert rate for editors who make between two and nine changes a month grew from 5 to 15 per cent over the same period.

“This is evidence of growing resistance from the Wikipedia community to new content,” say the Palo Alto team. Chi told New Scientist that the changes could harm Wikipedia in the longer term by deterring new editors from taking part and so reducing the number of people available to spot and correct the vandalism that constantly threatens the encyclopaedia. “Over time the quality may degrade,” he warns.

Chi thinks that Wikipedia now includes so much information that some editors have turned from creating new articles to improving existing ones, resulting in more disputes about edits. Such disputes are not a level playing field because established editors sometimes draw on extensive knowledge of Wikipedia’s guidelines to overwhelm opposition in a practice dubbed “wikilawyering”.

Spam to blame?

The Wikimedia Foundation, the non-profit company that operates Wikipedia, has noted these changes and last month launched a strategic review of Wikipedia in an effort to understand them.

But one of the experts leading that review, Eugene Eric Kim of Blue Oxen Associates in San Francisco says that Chi’s arguments are only one of several possible explanations for the changes seen in Wikipedia. The high number of reverts, for example, may be due to the increasing use of spam software that inserts promotional text, such as links to company websites, into articles.

Kim says the review will report this time next year and that any Wikipedia editor can contribute to the process.

The Palo Alto team will present their analysis at the International Symposium on Wikis and Open Collaboration in Orlando, Florida this October. A blog post by Chi summarises the study.