It’s important to remember that there are two different kinds of
configurations on a Debian system. _System-wide configuration_
affects all users. System-wide settings are made in the /etc
directory, so you generally must be root in order to change
system-wide settings. You might configure the way the system
connects to the Internet, for example, or have web browsers on the
system always start on the company home page. Since you want these
settings to apply to all users, you make the changes in /etc. Sample
configuration files in /etc include /etc/X11/XF86Config,
/etc/lynx.cfg, and /etc/ppp/options. In fact, nearly all the files
/in /etc
are configuration files.
_User configuration_ affects only a single user. Dotfiles are used
for user configuration. For example, the file ~/.newsrc stores a
list of which USENET (discussion group) articles you have read and
which groups you subscribe to. This allows news readers such as trn
or GNUS to display unread articles in the groups you’re interested
in. This information will be different for every user on the system,
so each user has his own .newsrc file in his home directory.