Telemarketing exists to annoy people. The companies that engage in this form of sales say that it exists to help them sell products, but we do not have to get too scientific to compare the amount of annoyance telemarketing creates with the number of sales it actually makes to see which purpose is more greatly fulfilled.
So a fellow who plays with artificial intelligence designed a program that will respond in such a way as to keep the telemarketer on the line as long as possible. and thus maximize the amount of time he or she wastes instead of just dropping them and letting them move onto the next call.
I kind of like the idea as a concept, but would probably not use it myself. For one, setting up the robot encounter involves a toll call, and the whole idea behind never responding to telephone solicitations is to not spend my money. For another, while I have no qualms about wasting the time of any of the operators working for some of the shadier companies that don't care about do-not-call lists and other legal niceties, I'm less comfortable dragging down job performance for someone who may really need that job.
My preferred method of dealing with telemarketers is to not pick up the phone if I don't recognize the number. Legit callers can leave a message and I usually call them right back. But if for some reason I'm stuck with a telemarketing call, I say, "I don't respond to phone solicitations, but thanks for calling. Bye." Then I hang up. I think being polite to people matters, and being polite to people I'd rather be impolite to probably matters more.