Aptus Consultants

It found the social networking behemoth not only had the largest audience of the top 75 social media sites – at 22.8m unique users in September 2009 – but accounted for three-quarters of time on social media sites, up from 63% in 2008.

Facebook’s gain in share of time spent on social sites has been at the expense of others such as YouTube, whose share fell from 12.7% in September 2008 to just 8.4%.

Alex Burmaster, communications director for the UK and EMEA at Nielsen Online, said, “The average person who visited Facebook in each of the last 12 months will have spent 70 hours 26 minutes on the site during that period. Based on the ratio between time spent by Facebook’s average visitor in September 2008 and the heaviest 55% of visitors, it’s likely the average heavy user will have spent over 125 hours on the site during the last 12 months.”

The research also found rival social networks Bebo and MySpace had continued to lose ground to Facebook. MySpace’s audience figures dropped from 5m in September 2008 to 4.16m in the same month this year, while Bebo’s dropped from 4.44m to 3.15m. The site that had the largest growth was micro-blogging site Twitter, which grew its audience by 1,959% over the year to September.

The research found UK internet users spent 11.1bn minutes on the top 75 social media sites in September, an increase of 83% in the past year.

It comes after research from IT services company Morse found office workers waste an average of 40 minutes a week on social networks, costing the British economy an estimated £1.38bn.