When Harry Bolston says that the Lang family moved to Smallville in 1938, this is a reference to the year that Superman was created.
In Lex Luthor's future sequence, he is wearing a glove on his right hand. This is a nod to the comics where, at one point, Lex wears a glove due to hide the effects of long-term exposure to kryptonite.
The name Cassandra references the Greek figure of the same name who was cursed with the ability to foretell the future but never have anyone believe her.
A sequence showing Lex Luthor as President of the United States was filmed on the set of The West Wing (1999). It also mimics the comic cover of when Lex became president.
This episode formed part of Alfred Gough and Miles Millar's initial pitch to the studio for the series.