A new study by Echo (Electronic Communication Harassment Observation) at Bedford University has concluded that cyberstalking is now more common than face-to-face harassment with many victims finding themselves pursued by complete strangers online.
Men are also much more likely to be harassed than previously thought.
The findings come from the first study of its kind to look at the extent and effect of cyberstalking, taking in social networking sites, email and mobile phones.
Emma Short, psychologist and co-author of the study, said the crime was not taken as seriously as it should be.
"There is a lack of understanding of the impact of this behaviour. One of the biggest questions was, 'Is there psychological harm?' Worryingly, a third experienced this. Not just stress, but a clinical record of psychological harm," the Telegraph quoted Short as saying.
"There have been threats to kill. They give the impression that they know where their victims live and can get at them physically. There is a lot of damage to or loss of reputation, people being compromised by false allegations," Short added.
The study has revealed the profile of perpetrators to be radically different from those who pursue victims face-to-face.
It found that nearly 40 per cent of cyberstalking victims are men, in contrast to past studies which have identified women as much more at risk from face-to-face stalking.
The study will be released next week with the backing of the Crown Prosecution Service.