It has almost become an occupational hazard for teachers. All too frequently they become the victims of smears on social media. Earlier this month, the growing problem reached the High Court in Dublin when Twitter was ordered to remove "grossly defamatory and offensive" pictures and tweets about an Irish teacher.
The female teacher, based in the Middle East, was featured in a Twitter profile with sexually explicit posts. She told the court she had not created or had anything to do with the profile, which had caused her a great deal of stress and alarm.
The Twitter profile has since been removed.
It is not clear who created the defamatory posts, but there are a growing number of cases where teachers are becoming the targets of abuse.
Pat King, general secretary of secondary teachers' union the ASTI, said: "There is a definite increase in the number of teachers and members of school staff contacting the ASTI for advice in relation to Facebook, YouTube and Twitter postings by students."
Among the recent problems dealt with by the ASTI were:
* Students setting up impostor Facebook accounts in a teacher's name.
* Derogatory comments by students on social media.
* Students filming or taking photos of teachers using mobile phones.
A fairly thick skin has always been an essential trait for those working at the chalkface.
Teachers have always had to tolerate anonymous abuse posted on blackboards or graffiti on the back of toilet doors.
For almost a decade, they have also had to put up with anonymous rankings and comments on RateMyTeacher.com.
When lurid sexual comments and pictures are published to the world on the internet, the depth of hurt can be that much deeper.
Mr King says: "Material which constitutes malicious gossip, harassment, humiliation or defamation can have a serious impact on a teacher."
Social media abuse can lead to expulsions or suspensions. In July 2012, four pupils at Oatlands College in Dublin were expelled after abusive remarks about two teachers were posted on Facebook. Two of the students were reinstated on appeal.
Twenty-eight students at Colaiste Chiaráin in Croom, Co Limerick, were suspended last year after they "liked" an explicit post about a teacher on Facebook.
So what can a teacher or principal do if they become a target of abuse?
If they know the perpetrator, they can tell them to remove the material and tell the principal. One of the problems is that the defamatory posts may be anonymous.
Kate Colleary of Eversheds Solicitors says: "Teachers who are the target of abuse should contact the website to ask for the posts to be taken down.
"If the material is defamatory, sites should act to remove it, otherwise they could be liable for damages."
Mr King says: "It is vital that students understand there are boundaries in relation to what they can post about any individual (including their teachers) on these platforms.
"Schools should have clear and robust statements setting out what the school regards as unacceptable online behaviour," says Mr King.
Social media sites are so pervasive that a complete ban in schools is not always practical. Many schools use sites such as Twitter and Facebook as learning tools.
It is also questionable whether a blanket ban would have that much effect. Even if students are banned completely from using social media in school, damaging material can easily be posted about teachers outside school hours.