A recent report on social networking examines the spectacular growth and stickiness of the most popular services. Stickiness is a term referring to the ability of a site to retain clients, members or visitors and to have them return on a regular basis.

So which social networking site grew the most and was judged to be the most sticky? I’ll give you one guess :).

MySpace

Nielsen Netratings reports that April’s top 10 social networking services collectively grew from of unique audience (US) of 46.8 million in April last year to 68.8 million this year. That represents a collective growth rate of 47%. The impact of social networking has been huge, with 45% of the active US online population now visiting at least one of the top 10 social networking sites each month.

In terms of unique visitors & year over year growth (U.S. home and work), MySpace was by far the leader:

MySpace - 38.36 million - +367%
Blogger - 18. 51 million - + 80%
Classmates - 11.67 million - + 10%
YouTube - 12.51 million - +10%

2 social networking services out of the top ten experienced a drop in unique visitors - MSN Groups and AOL hometown. YouTube, a video sharing service, is an interesting one to watch given that it’s only been in existence since February 2005. Another solid performer was MSN Spaces, which managed to achieve 286% year over year unique visitor growth.

As for stickiness (March visitors returning in April), MySpace led the pack with 67% of visitors returning, followed by MSN Groups (58%), Facebook (54%), Xanga (49%) and MSN Spaces (47%)

Learn more about MySpace’s sticky secret sauce in my post “MySpace - why so successful?”

My other blog posts regarding MySpace

Read the Nielsen-Netratings social networking report (PDF)