We talked awhile back about how the fuel-consumption display in the Toyota Prius inspires drivers to try and get even better mileage out of their hybrids. Now (or at least, recently--I'm a bit behind, so thanks, Grist, for catching me up ), Nissan is putting similar devices in all of its cars. "You will become a little less lead-footed if you can see what putting your foot to the pedal does to your fuel economy," spokesman Tony Pearson told USA Today. What do you think: Would knowing your real-time mpg encourage you to drive better, or less? And what other ways could technology be used to prod people toward conservation? A note on your computer sign-in screen telling you how much energy you'd wasted by leaving it on overnight, perhaps?