Security software firm Sophos has conducted a report on growing security risks on social media sites.  As reported in Mashable, the report found a near 70 percent rise over last year in users claiming to get malware through social nets.  Sophos surveyed users and found 36 percent said they received malware through sites such as Twitter, MySpace, Facebook and LinkedIn, and 57 percent said that they have been spammed through these sites.  The firm also surveyed about 500 businesses and found 72 percent of them look at social media sites as risks to their company.  Among them, 60 percent pinpointed Facebook as posing the biggest threat.  Read more at Mashable.