This is interesting, a company called A Data, is releasing a SD card with a small "E ink" readout that will allow you to see how much space is left on the card just by looking at it. The way it will work, according to Oh Gizmo, is that when you insert the SD card in a mem reader device, it will update the display to show how much remaining space is on the SD card. When you take the card out, the text will stay on the E ink display until you place it into another device.
E ink is the method of displaying text like what you see in Sony’s new Sony ReaderEbook device. The text written in this format claims to be easier on the eyes to read and uses very little power (in the Sony’s ebook device, it only uses power to change pages, none to display the page). This seem’s like a good idea, I can really see this becoming the standard on all mem stick type devices…thats if it isnt too expensive.
Source: Oh Gizmo!