This is the fourth time Lois has learned Clark's secret. The first three times were in Spell, Blank and Crimson.
When Clark reveals to Lois that he has X-ray vision, she covers her chest. Chloe did the same thing in "Blank" when Clark told it to her.
While Clark has always been bulletproof, this episode first clearly shows glowing bullets bouncing off him in normal speed, similar to a scene in Superman Returns.
This is the fourth time that Lois has learned Clark's secret. The first three times were in "Spell", "Blank" and "Crimson". When Lois finds out about Clark's secret, she says that she shouldn't call him 'Smallville' anymore. She said the same thing in "Blank" before her memory was erased.
Lois doing Clark's interview about his origins and heritage is a direct reference to the interview from Superman: The Movie.