A total of 41.1m minutes were spent on Facebook in August, equating to 9.9% of total time online. This compared to 39.8m minutes (9.6%) on Google sites, including YouTube and Google.com.
Yahoo sites received a total of 37.7m minutes of dwell time (9.1%), down from 12% for the same period in 2009.
Both Facebook and Google have received considerably more traffic over the last year, climbing from around 5% each in August 2009.
All three web giants have made significant moves over the last 12 months to obtain a greater share of traffic and increase time spent on their sites.
Google has made deals with broadcasters, film studios, sports bodies and record labels to show more long-form content on YouTube, while Yahoo has embarked on a year-long ad campaign to revitalise its position in the portal market.
This story first appeared on newmediaage.co.uk