St Marys police recently held a community meeting to discuss cyber safety.
A police spokesman said social media could be useful for many reasons, but warned people to think carefully before providing personal details.
"Keep your personal information private and do not post your address or contact details," he said. "Consider the information you share and consider the photographs you post.
"What can be seen in the background?"
Police said cyber safety was a concern for adults as well as children and teenagers.
"From privacy concerns to identity theft and cyber stalking, there are many hazards that you need to be aware of and ensure you maintain your private information," the spokesman said.