This question is the topic of the dead media project (http://www.deadmedia.org/), which is itself dead.
My favorite nominations:
The Myriorama. Once you have a motion picture, a motorized three-mile-long panoramic painting on rollers (shown while a performer narrates and plays the piano) fails to draw a crowd. Although actually now that I think of it I would pay to see a myriorama today.
So, can anyone come up with another information technology that has definitively and verifiably vanished completely from use? Specific products don’t count.