This episode retcons Pinkie Pie's flashback from "The Cutie Mark Chronicles" by giving Pinkie Pie an extra sister in the form of Maud Pie, though it's possible that Maud's absence in Pinkie's flashback is due to the result of her storytelling.
This is the ninth time Twilight does not fly.
Friendship Report: The ponies learned the one thing that makes them share a bond with Maud is seeing Pinkie happy.