It's been around for a long time. I worked for one in seatlle in the late 80's early 90's. KJET 1600 am (actually 1590, but 1600 sounded cooler !)
Our comupter was nicknamed OTTO-PILOT. Because that is exactly how it worked. We put our voices on tape, changed them at the shift....had a lot of carts, and taped music...and just let it fly.
Sometime the trigger tones ( you couldn't hear them) wouldn't work.
It was a gas though...I'd go to the local bar after work...and they played our station there. People would FREAK when they heard me on the radio, and I was having a drink.
Alot of the time...no one was around so I would shut the machine off and do it live. I didn't like the automated deal either but we were a no-budget statoin that was run by KZOK until they sold us.
Then they said I wouldn't fit into the new format......I can't figure out why. When I knew it was going down, I told people to call in and write in protest, and then started calling the HIGHER ups "Weezils in business suits".
Im pretty sure I was not popular at that point.