Insert a scary ghost noise here... ooOOooOo..
Of course, the term sounds scarier than it is, but it isn't something to ignore either. A less colourful name for it is 'standby power draw'.
To put it in simple terms, a vampire load is any draw on electricity by an appliance or device even while it is not in use. The draws are usually fairy small where the device is in a low-power sleep or 'standby' mode. The first culprit to come to mind is likely the computer in sleep mode, but many other items might not come to mind. The LED-light switch on a power bar. The mobile device left on charge after the battery is full. Or bigger appliances like the TV that has to keep a small power draw on so that the system is ready to respond to a signal from the remote control to turn on.
There are [lots of other little draws] constantly going on in the house. And while small power draws are not horrible on their own, they can add up pretty quickly. If you click the link just above you'll see that some items draw more than others, making them a higher priority to deal with.
Fortunately, there's no stinky garlic required for getting rid of these little vampires. Some of them are actually pretty easy to eliminate: plug items like TVs, cable boxes and game consoles into a power bar and turn the power bar off when the items are not in use. You'll need to turn the bar back on when you want to use them, but that is not a particularly onerous task in trade for savings on the electrical bill.
Hydro One has some [other tips and suggestions on their site], as well. But essentially it comes down to unplugging or "unpowering" items when not in use or actively charging, whenever possible.
