Websites relying on user-generated content have increased dramatically in the UK, new statistics reveal.

Figures released by web monitoring company ComScore show Wikipedia as the 16th most visited online property in July 2006 with 6.5 million visitors (up 253 per cent compared to a year ago).

Other sites that rely on user-generated content in the Top 50 UK list include MySpace (up 467 per cent to 5.2 million visitors), Piczo (up 393 per cent to four million visitors), YouTube (3.9 million visitors), and Bebo (up 328 per cent to 3.9 million visitors). 

Bob Ivins, managing director of ComScore Europe, suggested that so-called Web 2.0 sites clearly encourage participation.

"Many of the sites experiencing the fastest growth today understand their audience's need for expression and have made it easy for them to share pictures, upload music and video, and provide their own commentary, thus stimulating others to do the same. It is the classic network effect at work," he said.

ComScore also analysed the engagement levels among visitors to the top five user-generated content sites and those visiting the remaining sites that comprise the Top 50 in July.

The results show that, on average, the top five user-generated content sites exhibit higher levels of user engagement than their counterparts across all engagement measures.

Collectively, the leading sites draw more frequent visits than non-user generated content sites (4.2 compared with 3.5 average usage days per month), longer periods of engagement (79.9 compared with 33.2 average minutes per visitor), and more pages viewed (217 compared with 52 average pages per visitor).

Users of the top social networking sites demonstrate particularly high levels of engagement, with visitors to MySpace and Bebo averaging at least five usage days, two hours of use, and 300 page views per visitor during July.

"By analysing a variety of engagement metrics it is clear that [user-generated content] sites, and in particular social networking sites, represent potentially fertile ground for advertisers and marketers," said Ivins.

"Users on these sites visit more frequently, stay longer and view more content, which means more opportunities for marketers to communicate messages.

"The challenge right now is to determine effective ways to integrate this messaging while maintaining a positive user experience."