Employees should make use of privacy controls on most social networking sites, Stephens said.
John Simpson, Consumer Watchdog's Privacy Project director, criticized "corporate spying" in the name of security.
"Actually much of what is discussed [in the Gartner report] is unwarranted snooping in people's personal lives," he said in an email. "There is no valid reason for it and companies that engage in such activities should be called out for their unethical activity."
A number of available products will monitor social media use by employees, and many public relations firms also will monitor social media as part of their service, Gartner said. Security organizations also are beginning to pay attention to social media, not only for internal security surveillance, but also to detect emerging threats, the analysis firm said.
"The problem lies in the ability of surveillance tools and methods to produce large volumes of irrelevant information," Walls said in a press release. "This personal information can be exposed accidentally or become the target of voyeuristic behavior by security staff."
Companies considering new monitoring programs need to make sure they are complying with the laws of every country they operate in, Walls wrote in the report. In addition, if companies want to monitor employee social media activity on employee-owned devices, they will need to get permission from the workers, Gartner said.
Security staff should get permission from the company executives before monitoring, the report added. "Surveillance is an unusual activity that requires specialized capabilities and clear authority from senior management," Walls wrote.
Grant Gross covers technology and telecom policy in the U.S. government for The IDG News Service. Follow Grant on Twitter at GrantGross. Grant's e-mail address is firstname.lastname@example.org.