No surprise here, the No. 2 spot went to Facebook, as the Menlo Park, Calif.-social giant has grown to be the most widely used social network and one that is frequently used by businesses to reach out to customers. Only 41 percent of organizations that have policies governing Facebook use have an archival and supervision system in place to enforce them, the Smarsh study found. Social media messages were the fifth most requested data type requested by regulators, the study found. Requests for messages made on Facebook, LinkedIn and other social networks grew by 7 percent over the previous year, Smarsh said.