3. Beepers

Have you ever seen the very first cell phones? They are approximately the size of a watermelon. Ok, maybe not that large, but still waaaaaay too big to carry around, so back in the 90's, people carried around a device that would "beep" you when someone wanted you to call them, and you'd either find a pay phone or walk over to your car to call them on your watermelon sized cell phone. Yes, they enjoyed a good run for a couple of years, but with the advent of smaller phones, they have dwindled into obscurity.