Create File Permission Level: APPEND

[zadjii]

Different from write permission, this would allow clients to write a new file to a directory, but then no longer have access to it. This could be used for writing messages to a user's inbox, then letting the user do whatever with them.

Although, I don't totally love that. that makes it hard (impossible) to view sent messages, message threads, etc.

Regardless, it could be used for a lot of purposes. It's an option.

[zadjii]

When a user has APPEND permissions on a directory, they can add new children to that directory. As the creator, they'll automatically get full permissions on the file.

When a user has APPEND on a file, they can write to the end of the file, but they need WRITE o be able to wholly re-write the file.