The short passage Steve McGarrett (portrayed by Jack Lord) uses to test the answering machines, "If a man does not keep pace with his companions, perhaps it is because he hears a different drummer...." is from "Walden" by Henry David Thoreau, and is a reference to Thoreau's belief in Transcendentalism, where having fewer possessions allows a man more freedom and to be more of a non-conformist.
Steve tells Kono to put together a "boiler room" with HPD on the illegal operation. A "boiler room" is the room or department where the real work of an organization goes on. This would be checking everyone involved in the illegal operation.
Bill Bigelow's role as John Malcolm is fairly prominent, but he receives no mention in the end credits, unlike Sheri Rice as Joanna Grayson, who doesn't have a single line.
Michael Strong and Patricia Herman were also featured together in the season 6 show " One Born Every Minute". They played the roles of husband and wife.