The UK's Crown Prosecution Service (CPS) has published new guidelines to crack down on cyberstalkers.
People found harassing others through social networking sites could now face prison sentences of up to five years.
Alexis Bowater, chief executive for the Network for Surviving Stalking (NSS), said the new guidance will go a long way to improving the lives of victims.
"Recognising, in particular, new forms of stalking such as cyber stalking is ground-breaking," he said.
More than one million women and 900,000 men are stalked in the UK every year, according to the British Crime Survey, but until now there has been very little research available about cyber-stalking, said the NSS.
Nazir Afzal, CPS community liaison director, said cyber-stalking should have been handled better in the past.
"We need those affected by this crime to know that we have listened carefully to concerns raised by victims and stalking support groups, and we recognise how serious and how distressing this behaviour can be," he said.
Psychologist Dr Emma Short said there are stalkers for whom the internet and mobile phones are just convenient 'tools of their trade'.
"But we think there are also vast numbers of internet users who are engaged in harassing behaviours simply because they don't know the rules of appropriate on-line communication," she said.