Comment 7 for bug 48734

"On most multi-user systems, there is some level of cooperation (if not trust) among the users - they'll be members of the same family, or friends, or co-workers, or whatever"

I don't think you can rightly make that assumption. Even if it is true in most cases, it is better for people to opt in to sharing files than to have to opt out of it.

"and it is useful for them to be able to share files reasonably conveniently (e-mail is an awful solution to this). It's easier to create a private directory for the things you don't want to be public than it is to figure out how to open up your home directory so that just a few things can be read."

How about just creating a shared directory, then?

644 is pretty useless for sharing (for example, if I want to share a music collection with my whole family, they cannot right to my music collection, and I cannot write to theirs, so we would have to do a lot of duplicate checking or have only one person add songs, which would be ridiculously cumbersome).

/home/username would be 600 by default

/home/shared would be 660 or 666 by default

What's wrong with that scenario?