I don't agree on that. The file must be writeable by the user which "runs" Apache (which varies from system to system, it could be "apache", "nobody" or whatever). This can happen in a lot of manners (e.g. file is owned by that user, and user-writeable; user is within file's group, and file is group writeable...), which doesn't necessarily imply world-writeability. In case the file doesn't exist yet, the above consideration applies to the directory.