The LED light bulb is more than ten times the efficiency of regular incandescent lighting, so it can save the world hundreds of billions of dollars in electricity costs.

The killer app that got the world ready for appliances was the light bulb. So the light bulb is what wired the world. And they weren't thinking about appliances when they wired the world. They were really thinking about - they weren't putting electricity into the home. They were putting lighting into the home.

A light bulb went off.

I just think a light bulb went on.

Going blonde is like buying yourself a light bulb!

We forget just how painfully dim the world was before electricity. A candle, a good candle, provides barely a hundredth of the illumination of a single 100 watt light bulb.