Teachers in Scotland have been warned that their use of social networking sites to talk about their social life and employers could put their careers at risk.
The Scottish Secondary Teachers Association (SSTA) believes teachers can reveal too much personal information on sites such as Facebook and Twitter.
The union also fears they could become overly familiar with pupils.
The General Teaching Council of Scotland is preparing new guidelines on social networking sites.
This follows a number of recent cases brought before the GTC's regulatory body, the BBC reported.
Jim Docherty, assistant secretary of the SSTA, said that teachers should follow his advice: "First thing is don't bother telling anybody else about your social life. Nobody is interested about your social life and it doesn't help.
"Secondly, never make any comment about your work, about your employer, about teaching issues in general.
"There is always a possibility it will be misinterpreted," Docherty said.