So let's assume I have a file inside my ~ directory called "file.txt". My ~ directory (aka user) has it's permissions set to 700. Now, let's say my file has permissions set to 664, meaning I want anyone in my group to be able to read and write that particular file. The problem is (s)he can't even access it because my home directory won't allow it. So as long as I keep my ~ directory permissions fixed to 700 only me and root can access those files, regardless of their individual permissions, right? If so, why bother set a file to 600 instead of the standard 644? In other words, is there a point to change the file mode creation mask to 600 for that kind of files (assuming you have more than one user in your system and that your ~ directory permissions is set to 700)?
Ok I found the answer here
If you create a file underneath ~ which is readable by others and then create a hard link to this file in an accessible path, they'll be able to read it regardless of the permissions on ~.