The Lamar County school board approved the policy earlier this month after becoming concerned that casual contact between teachers and students would be unprofessional.
"The only intent is to limit the personal communication between teachers and students," Superintendent Ben Burnett told The Hattiesburg American newspaper. "We don't need to let it cross the line between professional and personal communication."
Burnett said the policy won't keep teachers or students from creating profiles on sites such as MySpace or Facebook, which allow users to share personal information and communicate over the Web.
"This just keeps them from communicating socially through those kinds of means," Burnett said.
No incident led to the policy, which was enacted at the suggestion of the school board attorney. The board has yet to set penalties for violating the policy.