Chinese social networking site Renren has 131m registered users, but only 31m visit at least once a month

"According to its prospectus, Renren has 131m activated users – people who have been through a multi-step registration process which involves submitting personal information, and replying to a verification e-mail. But it later disclosed that only 31m of them use the service at least once a month.
[...]
According to bankers, Renren generates just 80 cents per user compared with $4 for Facebook. “Monetisation at Renren is two years behind Facebook – that’s where the opportunity is,” said one banker working on the deal."
Source:  Financial Times, 29th April 2011