When writing about Powerset this week, I covered how its hopes to gain Wikipedia users was complicated by the fact that Wikipedia itself gets so many people from search, rather than direct navigation. New stats (PDF) from Nielsen Online reaffirm this — four of the five top referring sites to Wikipedia are search engines, with Google by far the leader.

Here’s the rundown on top referring sites that generate home users from the US, for April 2008:

To explain further, the chart above shows that 61 percent of people who were referred to Wikipedia in some way came from Google. And top sites that generate work users:

All that traffic Google sends to Wikipedia is one reason that many suspect Google would like to have its own Wikipedia alternative. Google Knol – Google’s Play To Aggregate Knowledge Pages covers more about this, though that particular project has yet to happen.

Related Topics: Search Engines: Wikipedia | Stats: Popularity

About The Author: Danny Sullivan is editor-in-chief of Search Engine Land. He’s a widely cited authority on search engines and search marketing issues who has covered the space since 1996. Danny also oversees Search Engine Land’s SMX: Search Marketing Expo conference series. He maintains a personal blog called Daggle (and maintains his disclosures page there). He can be found on Facebook, Google + and microblogs on Twitter as @dannysullivan. See more articles by Danny Sullivan