A line from Herb's speech to Miles is inspired by the Gettysburg Address. Abraham Lincoln said "testing whether that nation, or any nation so conceived and so dedicated, can long endure." Herb said, "This firm cannot prosper... nor long endure..."
When Miles (George Clooney) gives his keynote speech to N.O.M.A.N, telling his audience that "love is good," he is adapting the line from Ivan Boesky's famous speech, in which Boesky assured his audience that "greed is good." In turn, Boesky's speech was reprised by Gordon Gekko (Michael Douglas) in the movie "Wall Street."
The logo on the door handle of the Rexroth mansion is the same as the logo for the Rich company in Ri¢hie Ri¢h (1994) where Edward Herrmann played Richard Rich marking the second time the actor has played a character with repetitive Rs in his name. This is likely a homage from the film makers to his previous role.
Right before Howard Doyle (Billy Bob Thornton) rips up the Massey prenup agreement he and Marilyn Rexroth (Catherine Zeta-Jones) have signed as a "present" to his bride, he tells the assembled guests that it is unusual for the groom to give his bride a wedding present. In point of fact, a large number of brides and grooms exchange wedding presents immediately upon taking their vows.