Corning, which amongst other things makes glass for LCD panels, produces an annual estimate for global LCD screen sales. Since it sells glass by the square foot (and doesn't really care about the sizes of the screens), it gives this estimate in billions of square feet, a discordance with the way we usually think about consumer technology that delighted me when I first heard it: "there will be 3.5bn square feet of screen sold in 2013".
This chart shows Corning's estimates since 2005. In recent years perhaps two thirds of this represents TV sales - the rest is computers and mobile devices.
The web is full of dramatic charts showing the growth of PC, smartphone or tablet sales. I've made plenty myself. But this chart speaks to a deeper and more fundamental point.
The display of, well, anything has been liberated from bulky, heavy CRTs or blocky black and white LCD screens. Today, the tech world is about pieces of glass, showing whatever content and interface you can imagine. It's almost as though the content is dematerialised. No buttons, no case, no bezel - everything is about the image. The image is the glass and the glass is the product.
If it's a yard across you bolt it to a wall and watch video on it. Smaller, and it goes on a desk and you use a keyboard and mouse. Smaller still, and it's called a 'tablet', gets touch and goes in a bag, and smaller still and it goes in a pocket, or on your wrist perhaps. But it's all just glass with a data connection.