This is the first episode not to feature Jack Shephard and Hugo Reyes played by Matthew Fox and Jorge Garcia who, prior to this, had been the only people to have appeared in every episode.
The first episode to not feature any flashbacks from before the plane crash.
The period of time between the plane crash and the end of this episode is 48 days. 4 and 8 are the first two "cursed" numbers.
The number 4: there are 4 survivors left from the tail section of the airplane by the time they reach the other camp; Ana Lucia, Libby, Bernard, and Mr. Eko.