Finally, a long overdue ecobit addressed to the self identified geeks out there. For the uninitiated, I'm not talking about the traditional circus performer type, but rather the computer performer type. Actually, anyone who uses a computer can listen up here, I'm reaching out to everyone from the difficulty double-clicking level to the setting your hard drive jumpers yourself level (and beyond, if that's too common for you.)
Computers were supposed to revolutionize office management by creating a paperless business space. Instead, they've virtually doubled paper output. To combat this plague, I'm going to suggest something that's been bothering me for a while: for the love of Pete, you do not need to print out a copy of every email you receive. That's the whole point of email: it's conveniently paperless.
On to the energy use of computers: in most situations, please remember to turn them off overnight, whether it's a home computer and you're going to bed, or an office computer that you leave at the end of the day. Certain computers must be left on, e.g., servers, but unless you're actively downloading the leaked copy of Star Wars Episode 2 (but you would never do that, right?) you don't need to leave your PC (or Mac) on overnight. Energy audits at nearby universities have discovered that they can save massive amounts of energy just by ensuring that office and laboratory computer pools are shut down for the evening.
Even if you're just not using it for a little while(i.e., away from it for more than an hour), it's still more efficient to turn it off for a period of a few hours. So go ahead, shut down and power down to cut back on the electricity bill: it's more money to pour into upgrades.