When Reid discovers that the two unsubs have been communicating with each other through the newspaper classified ads, the camera zooms in on one of the ads. But the ad shown was the message that Reid writes later in the episode when he is posing as the Hollowman to lure the Mill Creek Killer to a false dumpsite.
While sitting in the car the shooter throws the newspaper into the passenger seat. When the camera angle changes to outside of the car he is still holding the paper in front of him. The paper is gone again when the camera changes back to inside the car.
At around 11:40 or so when Hotch and Reid are in the apartment of one of the victims the grandmother tells the older boy to take the baby in the next room. He picks him up from behind while he's crying and carries him across the room. When the camera flips to behind him the baby is suddenly completely quiet and turned around facing the older child.
In one of the personal ads, 'different' is misspelled as 'differenct'.