"A tangible user interface (TUI) is a user interface in which a person interacts with digital information through the physical environment. Hornecker and Buur state that tangible interaction relies on tangibility and full-body interaction, and gives computational resources and data physical form.
Research, not products
Currently, most tangible interaction concepts are explorations of the possibilities of tangible interaction; design/research projects as presented by the tangible media group at MIT, Joep Frens' Rich Interaction Camera or these students from IDE. So why am I - being a conservative, usability-minded interaction dinosaur - interested in Tangible Interaction? Because I see tangible interaction as a way of making the interaction less conscious, and demanding less resources (attention, effort, time). And as Krug put it: we don't want things to make us think. (It should be mentioned that there are some that disagree with tangibility being a gateway to easier interaction: misconceptions about tangible interaction).
Tangible interaction in a shop near you
So I set out to identify examples of tangible interaction in products that are already among us; that you can actually buy, right now, in a shop near you. They might not be as radical and inspiring as the tangible interaction research/design concepts mentioned previously, but I think that though they are more modest, these are examples of products that really make a difference by providing tangible interaction. (By the way, the numbers are not intended as ranking or something.)
1) PowerMate: a physical volume button for your computer
The PowerMate in essence is the volume button from your teenage stereo set, but now in brushed aluminum, with a blue light beneath it (how cool is that!) and connected to the USB port of your computer, allowing you to quickly and quite exactly adjust the volume in media playing programs. As opposed to clicking that annoying little icon, or hastily accessing your media player if you accidentally play ACDC right after listening to Jewel." (Continued via uselog.com) [Usability Resources]