A social media policy (also called a social networking policy) is a corporate code of conduct that provides guidelines for employees who post content on the Internet either as part of their job or as a private person.
The goal of a social media policy is to set expectations for appropriate behavior and ensure that an employee's posts will not expose the company to legal problems or public embarrassment. Such policies include directives for when an employee should identify himself as a representative of the company on a social networking website, as well as rules for what types of information can be shared. Almost all social media policies include restrictions on disclosing confidential or proprietary business secrets or anything that could influence stock prices.
Some social media policies are ten pages long with very specific rules -- mandating that employees can not use their enterprise account passwords for social networking sites, for example. Other policies are quite broad. The Twitter policy at Zappos simply says "Be real and use your best judgement."
See also: acceptable use policy