Wikimedia Foundation Inc.'s popular Wikipedia online encyclopedia cracked the top ten list of most popular Web sites in the U.S. for the first time in January, according to comScore Networks Inc.
Wikipedia sites ranked ninth with 42.9 million unique visitors last month, ahead of the sites from The New York Times (number 10), Apple Inc. (number 11) and Viacom International Inc. (number 12), comScore reported Thursday.
Wikipedia, which already ranked in the top ten list of most popular Web sites globally, has been quickly gaining popularity in the U.S., where its parent company, the non-profit Wikimedia Foundation, is based.
In January of last year, Wikipedia sites ranked in the 33rd spot with 18.3 million unique visitors. By July, it had climbed to the 18th spot on the list with 28.1 million unique visitors, and in November it ranked 12th with 39.1 million unique visitors, according to comScore.
In doing its tally for Wikipedia, comScore also counts visits to other Wikimedia sites, like Wiktionary, Wikiquote, Wikibooks and Wikinews, but most of the traffic comes from the Wikipedia encyclopedias, a comScore spokesman said.
Wikipedia started in January 2001 with its English-language site, which currently has more than 1.6 million articles. The Wikipedia project has since grown significantly and has more than 5 million articles in more than 200 languages, according to WikiMedia. Access to Wikipedia is free. Volunteers contribute the encyclopedia's content, which can be edited by anyone accessing the sites.
Globally, Wikipedia sites ranked sixth in December with almost 165 million unique visitors, according to comScore.