My grandmother had a phone like this in her house on a farm in northern Minnesota.  She also had a party line which meant that just about anyone could listen in.  When you lifted the receiver to speak to a friend, you could hear faint click-like noises in the background which signaled that your neighbors had unhooked their earpiece and were listening to your conversation.  Sometimes they would interrupt to insert comments of their own!  You could tell them to hang up but often they ignored you and hung on the line.