MySpace was the top social networking site in the US during September, according to a new study.

Research by Nielsen notes the online resource had 59.4 million unique visitors over the course of the month, a rise of one percent on the same month in 2007.

Facebook came in second place with a total of 39 million unique visitors during the 30-day period.

This reflected a rise of 116 per cent on September last year.

Classmates Online, LinkedIn and Windows Live Spaces rounded out the top five.

In Nielsen’s Connecting the Dots blog, Suzy Bausch comments on the results, noting nearly half of the biggest social networking sites are also among the fastest growing.

She also states such sites are most popular – when ranked by composition index – among people over the age of 25.

"Many social networks are launched and fail, but with the right combination of reach and function, there is still room for others to ante up," Ms Bausch concludes.

In other news, a recent study by ExactTarget found email marketing messages are more likely to influence people between 18 and 34 to make a purchase than social network adverts.