Mac is to "Drop Box" as Windows is to...?

This morning at our faculty meeting my high school's IT/calculus teacher told our faculty about a folder he was putting on our school's server for students to put their assignments into. The problem that he described was that both teachers and students needed access to it, so he had to allow read and write permission for both groups. When I heard this, it reminded me of how I have my Music Technology class hand in their files and projects–they log into my laptop as a Guest and drop their assignments into my Drop Box. But what he described sent up security red flags in my mind–if students have read and write access into his Windows assignment folder, they can see each other's work! In my Mac OS X scenario, students cannot even see into my Drop Box, they can only drop in their assignments.

Does anyone know a viable solution for the Windows world which is similar to the Drop Box implementation on Mac OS X? (I can't believe I'm asking for Windows help on a Mac forum--I've been a Mac person since OS 7!).