50% of Companies Were Spammed from Social Networking Site in 2009

A survey of 500 companies found a 70% increase in spam and malware attacks via social networking sites in 2009, according to  security firm Sophos.

Facebook topped the list as the perceived riskiest of the major social-networking sites, followed by MySpace, Twitter, and finally LinkedIn.

The Sophos report (PDF) said that more than 50%  of the companies surveyed were spammed through a social-networking site last year and that 36% were hit by malware from such a site.

Analysis at Cnet.