LONDON: Some 29.4 million people in the UK accessed a social networking website in May 2009, up 9% year-on-year, with the typical visitor spending 4.6 hours on portals like Facebook and MySpace, figures from comScore World Metrix show.

According to the online research firm, 80% of the UK's online population visited a social network in the fifth month of this year.

This figure reached a high of 89% in the 25–34 year old age-group, falling to 86% for 15–24 year olds, 77% for 45–54 year olds, and 67% for the over-55s.

Facebook remained the top-ranking portal in terms of unique users, with visitor numbers rising from 15.1 million in May 2008 to 23.9 million in the same month a year later.

Bebo was in second place on this measure, although its audience declined in size from 11.9 million to 8.5 million over the same period.

MySpace also registered a drop off from 9.3 million to 6.5 million, while Twitter recorded a growth rate of over 3000%, as the number of "tweeters" rose from 90,000 to 2.7 million.

Windows Live Profile, run by Microsoft, received a total of 6.9 million visitors over the month as a whole, although no comparative figures were available for the previous year.

Mike Read, svp and managing director of comScore Europe, argued that "understanding audience composition is particularly important in a category such as social networking."

In particular, "there continues to be a misconception that social networking is the preserve of the young."

"While those under 35 years old are certainly the more prevalent users, there is both a sizeable and heavily engaged audience of those 35 and older as well," he concluded.

Data sourced from comScore; additional content by WARC staff