West Mercia police are warning the internet is making it easier for stalkers to research their victims.
Reports of the crime have increased since 2009 and north Worcestershire has the highest number of victims in the area.
Det Supt Paul Williamson said people need to be more aware of the amount of personal information they make available online.
"Cyber stalking is just another tool in a stalker's armoury," he said.
'Protect personal information'
According to figures from West Mercia police, there were 502 stalking cases reported in north Worcestershire between April 2010 and March 2011, an increase from 338 the previous year.
Telford recorded the lowest number of stalking victims, 89 between April 2009 and March 2010 and 111 during the following year.
Det Supt Williamson said the problem of stalking on the internet is getting worse.
"It will continue to increase while people don't sufficiently protect their personal information on things like social networking sites.
"The message we'd like to get across is that people do protect their personal information properly," he said.