Less than 10 percent of companies now monitor their employees' use of Facebook, YouTube, LinkedIn and other social media sites for security breaches, although many companies monitor social media for brand management and marketing purposes, said the report, released Tuesday.

New technologies and services are enabling the growth in employee monitoring, but companies will need to closely manage their monitoring efforts for ethical and legal issues, Andrew Walls, research vice president at Gartner, wrote in the report.

Monitoring can help companies avoid security problems such as employees posting unauthorized videos of company activities, Walls wrote. However, "there are other times when accessing the information can generate serious liabilities, such as a manager reviewing an employee's Facebook profile to determine the employee's religion or sexual orientation in violation of equal employment opportunity and privacy regulations," he wrote.

Earlier this year, that some prospective employers were asking people they interview for their Facebook passwords. That practice will "gradually fade," but companies will continue to monitor the social media conversations of employees and customers, Walls said in a press release.

Companies monitoring social media activity may face a backlash from employees, Walls wrote in the report. "Enterprise surveillance of employee activities on popular social media sites has led to disciplinary actions against employees that are often supported by the law but violate cultural expectations for free speech and personal privacy in most Western countries," he wrote.