In the scene where Lois is singing, it was actually Erica Durance singing, much like Teri Hatcher did when Lois went undercover as a lounge singer for a story in the Lois & Clark: The New Adventures of Superman (1993) episode I've Got a Crush on You (1993).
The shot of the 1940's Daily Planet signage is from the 1950's TV show Adventures of Superman (1952) starring George Reeves.
Clark wears glasses and a smart suit in his brief scene in the Daily Planet. He fumbles with them much like in the Superman movies. He also has a mild-mannered personality which references what he will eventually become in his real future.
This is the first time Lionel Luthor has been seen without a beard. He is clean-shaven except for a well-trimmed mustache.
This is the first and only episode of Smallville (2001) that features Lex and Lois having an intimate relationship, something which is more common in other depictions of Superman.