Massie Block is a fictional character so I do not know, however I think she would have some of the following apps:
Dream Closet. (iTunes) (It's basically where you can snap photos of your clothes and put outfits together with them. Sort of like a mannequin.
Lots of the latest songs. Think Rhianna, Britney Spears etc.
Anything fashionable!
Why don't you ask her on her AIM MassieBlockChat Twitter Massie_kurBlock or Blog Massiekurrblock.wordpress.com C ya there ;-)
Massie Block's phone in the "Clique" series is described as a pink rhinestone-encrusted Sidekick.
IPhone
According to the books she first has a Motorola razr and then she gets an iPhone.
Massie Block wears Chanel no. 5 and Chanel no. 19
Massie Block played "What Would You Rather" at her sleepover.
Massie Block is the protagonist.
massie block slept on the bottom bunk
William and Kendra Block.
Massie Block's mom's name is Kendra.
From reading all of the Clique books I would have to say no, Massie Block would never be caught wearing Aeropostale. Massie has finer taste and has the money to indulge in the finer things in life. But if you wear Aeropostale and want to be like Massie just start your own version of Massie Block, you don't have to be exactly like her. Do your own thing, I am pretty sure Massie Block does that!
The actress that plays Massie is Elizabeth McLaughlin.