Gossip Girl's voice-over at the end of the episode, "Daddy Warbucks don't grow on trees, at least not a tree that grows in Brooklyn.", makes mention of the 1943 semi-autobiographical novel, A Tree Grows in Brooklyn by Betty Smith.
Gossip Girl's voice-over at the end of the episode, "Daddy Warbucks don't grow on trees, at least not a tree that grows in Brooklyn.", makes mention of the character of Oliver "Daddy" Warbucks, from the comic strip Little Orphan Annie and Dick Tracy. He made his first appearance in the New York Daily News in the Annie strip on September 27, 1924.
As a muse to Aaron, Serena feigns being an ingenue at print modeling. She was hotly tipped to be the face for Eleanor Waldorf Creations in Bad News Blair (2007). So when she tells him she has no idea how to pose, she's just playing it coy.