This episode's title is a quotation from The Merchant of Venice by William Shakespeare, Act IV, Scene 1: "The quality of mercy is not strain'd, It droppeth as the gentle rain from heaven."
The movie that Don, Megan, Ted and Peggy see together (albeit inadvertently) is Rosemary's Baby (1968).
When Ted Chaough spoke with a Boston accent at the Ocean Spray meeting, he was told that Vaughn Meader was buried with Kennedy. Meader produced two comedy albums lampooning the Kennedy family that were quickly pulled from the market after the assassination. The first volume sold over seven and a half million copies and won a Grammy in 1963. Kennedy joked about it publicly several times and even gave copies to friends as gifts. Some biographers report that privately he was upset over it, and that Jacqueline was furious. Ironically, the first album was recorded live on October 22, 1962, the same night as Kennedy's Cuban Missile Crisis speech. The cast was aware of this but the audience did not know.
Ted tells Don that Peggy regards her Rosemary's Baby-inspired ad proposal as her "plop plop fizz fizz." This is a reference to a highly successful award-winning Alka-Seltzer print ad of the period.