You're welcome.
Since it appears your Earthlink email account is your primary account, you can use your primary .Mac email account for your website but regarding .Mac account aliases, the following was copied from .Mac Help:
You can create up to five email aliases to help prevent unwanted messages from being sent to your primary .Mac Mail account or for use with online groups and chat websites. For example, you might want to share your main .Mac Mail address with friends and family only and use email aliases for online registrations, purchasing products, joining mailing lists, and so on. This will help you better manage the email you receive and monitor the sources of unwanted messages. You can even send email using an email alias.
Seems to me it would be simpler to either add an email "alias"
to my Mail (the application that came preloaded on our iMac)
primary account, or create a new account.
As already provided, since your Earthlink email account is your primary account, you can use your .Mac email address for your website or go ahead and create/use an alias for the same but you cannot create another or separate .Mac account. Your existing account is it and you can create up to 5 email aliases at no extra charge. If you want another separate email account, you can purchase an email only account through your primary .Mac account at an extra charge which I believe is only $10/year.
If I understood your reply, I should be able to do either
one of these through the iMac Mail application?
Yes. This following was also copied from .Mac Help:
To set up a .Mac email alias, choose Mail > Preferences and click Accounts. Select your .Mac account and click Account Information. Click Edit Email Aliases to go to the .Mac website. Log into your account. Click Accounts, then click the Add button in the Email Aliases section. Enter a name for the alias and click Create Alias. The alias will then be available in the Account pop-up menu in new message windows.
If the Account pop-up menu doesn't appear in the compose message window, click the Action menu in the lower-left corner of the message header and choose Customize. Select the checkbox next to Account and click OK.
Messages addressed to your .Mac email alias will arrive in your .Mac account inbox.
Do you think creating another account would make me
less vulnerable to spam, than simply adding an "alias" to
my primary account?
It depends on how your email address is used on your website. If you include an Email Me link, you shouldn't be vulnerable to spam but if provided out in the open for anyone to see and for spambots that search the internet for valid email addresses provided out in the open on a website, etc., you will be very vulnerable to spam. But as already provided, if your .Mac email address associated with your .Mac account is not your primary email address and likely won't be, it doesn't matter but this is what email aliases are primarily designed for so I would protect my .Mac email account address in case you decide to make this your primary email address and use an alias instead on your website.
After several moves in a relatively short period of time having to change ISPs and my email address along with it since I formally used my ISP provided email account as my primary address, I now use my .Mac account as my primary email address since when moving and changing ISPs doesn't matter - I can always keep the same email address regardless.
