Four of the five top referring websites to Wikipedia — which grew almost 8,000 percent over the last five years — are search engines, led by Google, according to (pdf) an analysis by Nielsen Online, writes MarketingCharts.

In April, 61 percent of visitors from home, and 66 percent of visitors from work, to English-language Wikipedia (en.wikipedia.org) were referred from Google:

• Yahoo Search was second, referring 19 percent and 16 percent of visitors from home and work, respectively.
• Other search providers to make the top five referring destinations for Wikipedia were MSN/Windows Live Search and AOL Search.

"Search providers dominate Wikipedia's referring traffic because of its scope and value as an information resource," said Michael Pond, media analyst, Nielsen Online.

In the past five years, web traffic to Wikipedia has skyrocketed, increasing nearly 8,000 percent from April 2003 to April 2008:

"The site's rapid ascent, with audience levels comparable to popular brands such as eBay and MySpace, demonstrates the success of its collaborative nature," Pond said.

Such consumer involvement has in turn resulted in online buzz, particularly among blogs:

"Wikipedia content is inherently conversational, driving buzz in the blogosphere," said Pond. "Bloggers refer to and link to Wikipedia content, potentially driving additional traffic and interest in the site with their readers."