Posting your vacation plans online could be inviting thieves to stop by while you are not home, police warn. (Facebook)

Police are warning anyone heading out on a summer holiday to avoid mentioning their plans on Facebook or Twitter, or risk having thieves target their homes.

"We have this entire new world of opportunities for people to break into houses," warns Cpl. Janis Jean of the Saanich Police Department, north of Victoria.

It's now routine for police officers to ask robbery victims what information they put on Facebook and Twitter before the crime and if their online connections are true friends or potential suspects, according to Jean.

"Traditionally we'd say, 'Did you let the newspaper person know? Who'd you tell you were away?' And now it's also 'Did you post this on Facebook?' And it opens up a whole new world of potential suspects," said Jean.

The Saanich Police Department hasn't had a breaking and entering case directly tied to Facebook yet, but Jean still advises people do the online equivalent of leaving the light on when they are away from home, and keep their online profiles looking like they are still home.

Your friends are my friends?

Part of the problem is that many people haven't set their privacy limits on Facebook and they end up sharing their personal whereabouts with online friends they don't really know, according to Harjeet Sihota, an assistant manager at British Columbia Automobile Association on Vancouver Island.

"You don't want to be posting that you're going to be going on vacation at a certain date and time," he warns.

"You may be actually sending that out to a friend, but what's going to prevent someone hacking into their information and sharing it around?"

Sihota suggests curbing the desire to brag about a full day at the beach, going to a reunion, or a wedding, especially for people who have hundreds or even thousands of Facebook friends they don't really know.

Experts also warn that some social media websites such as Twitter can use smartphone and GPS technology to broadcast a users' exact location to the world, giving thieves a live update on when residents are not home.