I used to have a good friend who owned a chat line. But as of then, I had a pretty good idea of how it worked from the owner/operator POV.
I've never called one, but I have talked with the people who do all the jobs on one.
Just like the regulars down at the coffee house chewing the fat on a Tuesday night, or the regulars down at the corner bar yakking while nursing a Bud.
When I was a teen, in the late 90s (when everyone was still new to AOL) one girl from my class got hooked on these lines.
And like a modern message bord, after awhile you get to "know" the other folks, and interacting with them is more attractive than interacting with true strangers.
So there were a lot of people that developed the habit of calling at certain times of the week.
Women customers were given free or nearly so access.
I'm married and have no inclination to actually call one of these "party lines" or "chat lines", but I've always sort of wondered - these late-night chat lines must be profitable or else they wouldn't buy up all the advertising after 11PM. The only one which seemed remotely likely to accomplish its purpose was one for a gay chat line, where presumably everybody knows exactly what to expect. It's often called a "poor man's Internet." Some of these chat line like on Talkee Free Chat Lines ( Are free, well in the sense if you have free long distance. I know Northern Illinois University shooter Steve Kazmierczak picked up both women and at least one man off Craigslist, before he went on the shooting rampage, just for sex.Technologically, it operated like an ordinary business conference call.One female employee / contractor was on duty on the call as the "moderator" to keep the conversations going & spice it up if it got flat.They weren't "pay to chat with hot people on the other end" lines, they were local numbers you could call to leave messages for other people who called.You would also leave a "profile" so people could find you. I know we didn't pay for it, so I forget how it worked.