The Problem with Twitter and Facebook

House thieves have been given a leg-up by a new Web site that allows people to see whether or not you are at home -- thanks to information you're probably already posting online.

The site, Please Rob Me, works by taking data from sites such as Twitter and Facebook, relying on users checking into various locations. It then presents "opportunities" to visitors to "Please Rob Me" when it appears someone is not home.

In one 10-minute period, Please Rob Me presented 289 "new opportunities" as the site listed people who had checked into places such as work, the airport and the supermarket and posted their location on Twitter or Facebook.

Monash University crime prevention expert Dr David Baker said such a site was open to abuse and needed to be handled carefully.

"Hopefully it would be very few, but you could see some people use the site in a bad way," Baker said.

"If people have information that other people are going to be away on holidays or not there at certain times, then it's open for anyone to access. If someone's got that inclination to rob or to ... take revenge out on someone then that's a possibility."

But media commentator Brian Caulfield said the site was designed for fun.

"(The site is) about pointing out a big hole in everyone's personal security habits," he said. Site co-creator Barry Borsboom said it was a satire about people who expose themselves on social network sites.