At the end of the episode, Clark Kent states he can't believe Kyle Tippet and Bob Rickman used to be best friends, and asks Lex Luthor if he thinks they'll ever end up like that. This is an obvious nod to their future as archenemies.
When Lex Luthor is having a chat with Clark Kent at the Beanery, he mentions Clark to be quite similar to Atticus Finch. Atticus Finch was one of the famous characters from the Harper Lee's novel 'To Kill a Mockingbird'. Lex mentioning this is worth noting as Atticus Finch shows his willingness to support social outcasts and so does Clark when he shows his support to Kyle Tippet. In the Superman comics, To Kill a Mockingbird happens to be Clark's favourite book and To Kill a Mockingbird (1962) is his favourite movie.
Lana Lang asks Clark Kent what would he like to do later in his life, and he says: "I'm not sure, as long as it doesn't involve putting on a suit and doing a lot of flying." Later he wears a suit every day on his Daily Planet job and of course, flies alot as Superman.
The incident that Dr. Toby mentions in which Lex Luthor was stabbed is revealed in the episode Zero (2002) and is the same incident one that Roger Nixon threatened to blackmail Lex with in the episode X-Ray (2001).
This is the first episode in which Clark Kent wears a red jacket.