The wikipedia article is about incoming call queueing which I find good even from end-user (caller) perspective. What I found more interesting is that at least

The wikipedia article is about incoming call queueing which I find good even from end-user (caller) perspective. What I found more interesting is that at least some telemarketing call centers actually use outgoing call queues. The reason for this is: 1) They anticipate some percentage of unreachable numbers; 2) To maximize efficiency- operators don't spend time waiting on somebody picking up the phone, they are only engaged when there is someone on the line.