I have heard that various appliances, chargers, and electronics use electricity when they are plugged in even if they are “off.” For this reason I try to unplug things in my apartment when I know I will be gone for an extended period of time. The video below claims that 75% of the energy consumed by many electronic devices occurs when they are off but plugged in.
This article from the New York Times recounts the results from a study done by the Lawrence Berkeley National Laboratory for the Department of Energy. The study confirms that electronics use extra wattage when plugged in even though they are off. There is also a link within the article to a table that displays the estimated excess wattage used by various common household electronics.
The amount of energy used by these idle appliances is very small, however when magnified by billions of people, the amount of electricity that could be saved is more than significant. I plan on making “unplugging things” part of my routine in the morning and night. We leave things plugged in because it is an inconvenience to have to plug in our lamp or toaster every time we want to use it. If everyone could make unplugging become a habit then the collective effect could greatly impact society.