The BrightSign HD970 is a Solid State Digital Sign Computer. Its used for things like electronic menu boards.
I recently bought an ex display Bose headphone display stand for the QuietComfort 25 headphones on eBay, and when it arrived, it was fully functional, with a TV playing bose adverts which the user could interact with, I initially thought it was just a video loop with the play button controlled by some capactivie buttons on the front panel, however when I took it apart I found that the display was driven by a BrightSign HD970 display unit.
I took it all apart and had a play around with the SD card full of video, it quickly became obvious this was much more than a dumb video player, and with a bit of googling I found the BrightAuthor software available on the BrightSign website. After a quick download and some messing about I managed to build a new SD image that the unit boots from and plays my own digital advertising.