Let's start with the dark side. Though they generally hate to talk about it, most realtors acknowledge that things do go missing during open houses. "I walk through the home and see jewelry, credit cards and even cash sitting around," notes Scott Gormley of Oak Valley Mortgage in California on his blog.

Gormley says he always advises the listing broker to speak to the client to let them know "you can't always watch people that come into their open house."

A thief on Australia's trendy Mornington Peninsula took this one step further. He visited real estate websites, pouring over photos of vacation homes listed for sale. When he saw something he liked, he waited until midweek, then broke in and took it. When the thief was arrested, he had a garage full of plasma TVs and other pricey gadgets.

Think Canadians are more cautious? Ha! One of the million dollar-plus homes shown with photos on the welist.com website boasts a huge plasma TV and some pricey-looking works of art.

Perhaps the bad guys should think twice when temptation strikes. The homeowner may have installed the HomeSitter from Telus or Bell Canada's recently announced Home Monitoring System. For an initial cost of between $200 and $300, plus a monthly monitoring fee, your cellphone can let you know when somebody tries to break into your house.

You can get an automatic text message when the kids get home from school and punch in their PINs. Perhaps you'd prefer an SOS when a pipe breaks at the cottage. It's all possible, for a fee.

These systems are also being promoted as an "aid to independent living" for the elderly, who can be required to check in periodically. Getting an e-mail that Grandma did not enter her PIN as scheduled at 10 a.m. might be a sign that she passed on in her sleep, or at least needs a visit.

Bell also offers an optional video camera that its website calls "sleek and inconspicuous," conjuring up tantalizing possibilities for spying on the babysitter and her boyfriend. What you do with the system is up to you, Bell just sells it.

The telecom companies are clearly moving into a market long held by traditional alarm companies such as ADT and Alarmforce. These firms seem to be lagging a bit on the tech front, though ADT does allow you to update your alarm call-out list on a web portal.

In the U.S., AT&T has raised the bar for home-viewing obsessives with a US$9.95 per month service that beams streaming video from your home webcam to your cellphone. Two-way interaction with your home is also possible, allowing you to crank up the heat or make sure you turned off the stove.

Several years ago, there was a rash of garage break-ins in an upscale part of Calgary. Police reported that the bad guys had a device to spoof the signals of remote garage door openers.

This can be very serious for homes with attached garages, since the criminals can open the garage, close the door, and do a leisurely job of penetrating the house, often with tools provided by the hapless homeowner.

Hope is on the way in the form of biometric technologies such as the smartTOUCH door lock from Master Lock Co. of Wisconsin, which responds to your fingerprint on a touchpad.

Of course, no self-respecting Canadian wants to climb out of the car in the middle of the winter to chip the ice off a fingerprint reader, so they really need to come up with a remote version of this product for the Frozen North.

California-based Kwikset also makes biometric house locks. Even if your kids habitually forget their keys, they are unlikely to forget their fingers.

Other emerging home-security technologies include a hard disk that continuously records security video.

Think of it - now you can have convenience store-quality surveillance videos of your break-in to hand over to the police or post on the Internet.

Then there are also night vision cameras and, er, active countermeasures. One fellow I know has his alarm system zones connected to the corresponding zones of his sprinkler system. At least they're not lasers or something. "I don't want to hurt anybody," he says, "I just want to let intruders know that I know that they are there."

All the wireless cameras and alarm systems in the world are not going to help you if somebody is actively trying to kick down your door or smash in your windows. Of course you can always call 9-1-1, but a lot can happen in a few minutes.

Enter the Door Defender, manufactured by U.K.-based Willearn Ltd. This mechanical device is "fitted to the hinge side of the door frame and cannot be broken like a conventional door chain."

According to the website, it can withstand 750 kg of force.

When the bad guys came to shake down small-store owners in the Bronx, at least in the movies, they always said something like "You know, a lot of windows have been getting broken around here lately.

"For $20 a week, that won't happen.”

And it's true. Cheap window glass is remarkably easy for thieves to get through, so you might want to consider impact-resistant glass, especially for business premises.

Last but not least, put your digital camera or videocamera to use in the service of home and business security.

A few minutes spent documenting your possessions, maybe even reading the serial numbers onto the tape alongside the images, can save you days of trying to reconstruct what you owned for insurance purchases, if you are, indeed, unlucky enough to attract a thief.

(Tom Keenan is a professor at the University of Calgary and an expert on technology and its social implications.

He can be reached at keenan@businessedge.ca)