If you’ve ignored the whole user account thing up until now and feel practically illiterate when you run into Fonts folder pathnames, or references to setting up a separate account to test your font problems, relax: it’s simpler than you think.
Mac OS X is designed as a shared system, serving the needs—and preserving the privacy—of more than one user, whether the users are various employees or a few family members. If you’re the sole user, you have to put up with some nonsense that’s a result of the shared-Mac approach, with multiple places to store (and misplace) things, folders that seem to have the same names, and the concept of having an account on your Mac—an account with an administrator, who, in all likelihood, is you. You run into the surface issue of this approach every time you install software and you’re asked for an administrative password (and doesn’t that make you feel important?).
For most practical purposes, you can think of a Mac as starting with a single user account, a setup for a single user. Each user account has an owner, the person who has a password to use it. At least one user account has administrator privileges; the owner of an account with these privileges is allowed to make systemwide changes on the Mac that can affect all the accounts on it—like installing applications or updating system software. The first user account that’s set up on your Mac OS X machine automatically has administrator privileges. So, if you’re the only user, you have an account with administrator privileges. (You are the boss of you.)
The multi-user mindset of the operating system results in a hierarchy of resources and privileges:
System stuff: These are items the Mac needs to keep humming—everything from starting up, to putting a dialog on the screen, to opening an application when you double-click a document.
Communal stuff: Things that every user account can access, like applications, which are normally installed only once, in one place, and shared by everyone.
User stuff: Things that are private to each user, like documents (obviously) and environmental things like the Desktop background and preference settings.
If your Macintosh is set up with only one user account, you won’t see much difference between the system stuff (which, for the most part you get to ignore), the communal stuff (because you’re the commune) and the user stuff. But the operating system still observes the separation of system, commune, and user. If you do share your Mac with a spouse, child, or coworker, it may already have multiple accounts and you might be familiar with the effects of those separations.
How does this relate to fonts? For starters, there’s a Fonts folder for the system stuff, another one for the communal stuff, and another for the user (for each user on a multiple-account Mac). See? The multiple-Fonts-folders approach makes sense now that it’s in context, right? And the fact that there’s another Fonts folder if you have a Classic OS available on your Mac... that’s easy to absorb. And if you’re on a network, there might be a network Fonts folder for everyone to share—no big deal. There: five Fonts folders described in four sentences, and you’re not even breaking a sweat.
For more in-depth information about users and accounts, check out Take Control of Users & Accounts in Tiger (or Panther).