40% of social networking users quizzed have been sent malware via social networking sites, 90% increase since summer of 2009. 67% say they have been spammed via social networks sites, more than double the proportion less than two years ago. 82% of respondents felt that Facebook posed the biggest risk to security, with 82% saying it was Facebook the biggest threat to security. 59% believe employee behavior on social networks could endanger corporate network security, and 57% worry that colleagues are sharing too much information.
Source: https://thehackernews.com/2011/01/malware-and-phishing-increasing-via.html