Update: the Mattrunks blog (in French) adds comments and a possible enhancement that fits the Jr. Canest project, CC Smear Experiment : After Effects CS4 Project (361).
Also, Grayscalegorilla had more (earlier than AEP as well):
"Jr Canest was nice enough to share some screenshots of his AE comp with us. Check out all those keyframes! That’s what it takes to get that level of animation. It’s not scripts, nor expressions, nor plugins. It’s raw keyframe talent."