Not only does Seinfeld refer to frappes (thread below), but it just occured to me that the Seattle-based Starbucks people do too (Frappacino).
What's the deal? I really did think this was a Boston (or at most, New England)-only term. Don't New Yorkers and Seattlites use "milkshake" instead?? Is frappe popping up in any OTHER cities as well (Betty...OKC??).