What are some interesting inventions that fell into disuse?

 

What are some interesting inventions that fell into disuse?

Magnetic tape for information storage:

Extra care required when you had something valuable stored on it.

I remember I tried to avoid taking tram while having one in my pocket, and only using bus. The reason was couple of times I observed bright electric discharge between bow collector and wire, and next day I was not able to load the stored program. Still not sure if it was just a coincidence or not.