How is this any more of a risk than employees using email, or talking to people on the phone? What is so different about social networking sites that suddenly employees are going to start talking about company secrets rather than just catching up with their friends. What a load of tosh, as El Reg would say..

The problem of informational leakage is basically the same as email. But I bet more companies are aware of the danger of leaks via email (and thus they monitor and retain emails) than are aware of the same risk through "social media" sites.

Blocking user access to potentially useful resources isn't the answer. Education about identifying and dealing with Privileged, Private, and Secure Information is.

If you treat your employees like criminals, they'll ultimately start <i>feeling</i> like criminals. Better to empower them to make good decisions about disseminating company or customer IP, regardless of the medium.