"If you wouldn't put it on your classroom door, then don't put it on social media," Callahan said.
2. Check your privacy settings.
Many social media debacles stem from privacy settings that allow friends and strangers to see more than the user intended. If your settings designate posts as private, school districts and human resources managers can't require you to reveal them, said Mike McGonigle, general counsel for the Georgia Association of Educators.
"Set your privacy preferences, and check those privacy settings periodically because they change," he said.
3. Know what's allowed.
Schools are required by law to have a computer use policy, but many districts are behind in creating a social media policy. Become familiar with regulations and ask questions if they seem unclear, then use your conscience.
"Many teachers are now deciding not to be friends with current students to avoid a conflict of interest," McGonigle said. "But that's an individual decision. Know what your school requires and decide from there."
4. Be upfront with others.
A friend or colleague may post a photo or comment that could be considered inappropriate. If so, take it down and notify school administrators, McGonigle said. On sites such as Facebook, you can require approval before another person's post appears on your page – a good step, no matter your profession.
"Questions come up about others posting images or sending them to the school district," he said. "In my experience, districts aren't going to discipline the educator if they can tell someone is upset and has an agenda."
5. Know your rights.
Become familiar with online free speech and privacy rights. A Pennsylvania college student was dropped from a teacher training program after posting an image of herself with the caption "drunken pirate." A judge ruled against her free speech argument because of inappropriate comments she posted about school officials and the program. In Georgia, a school district proposed a policy that would require teachers to never add existing or former students as friends.
"There were no reasonable restrictions on the policy at all," McGonigle said. "It didn't trust educators to make the right decision, and it didn't pass."