Derpy, or a pony resembling her can be seen in the background singing "Winter Wrap Up" in the episode of the same name.
The official name of the pony most commonly known as Derpy Hooves is "Muffins".
Yes, many. She can be found in many places that sell mlp toys.
Well derpy was in the very first episode. I assume her biggest appearance though, would be when she has a speaking roll, which is in season 2, episode 14- The Last Round Up. She talks to Rainbow Dash.
Light purple mixed with grey. Also has blonde hair, yellow eyes, and a bubble cutie mark. Her original name is "Ditzy Doo" but presure from the bronies had Hub change her name to derpy in Ep. 12 of Season 2. HAsbro is quite mad, iTunes wont allow the episode onto iTunes. But hey, the bronies are happy, what else matters?
Well, she's in every episode at least once somewere in the background. Sometimes it's harder than others to find her. It's kinda like the where's waldo of the pony world! MLP forever! /) (\
The name of the school paper in MLP is the Foal Free Press.
Yes, there are several websites that offer My Little Pony fan fiction. Some of them are MLP: Rolepaying is Magic, MLP: Friendship Is Magic RPG, and Equestria Gaming.
no
yes
yes
The symbol for Salient Midstream & MLP Fund in the NYSE is: SMM.
MLP stands for My Little Pony. Most likely referring to generation 4, friendship is magic.