You enter account information in one place—the Mail, Contacts & Calendars pane of System Preferences—and thereby set up multiple apps. (Emphasis added)
Hmmm... I'm running OS X 10.5.8 and 10.6.8 installations at the moment, and that pref pane doesn't appear in either, nor did I see it in OS X 10.3.
Certainly that works with OS X 10.7. and 10.8. In System Preferences > Mail, Contacts, and Calendars (the icon is a blue circle with an @ symbol in it) you find essentially the same dialog found in Mail > Preferences > Accounts but with the option to select GMail, Twitter, Facebook, Yahoo, Aol., vimeo, flickr, or "add other account. The dialog in Mail > Preferences is even simpler and determines most email account settings from the email address itself without the need to select a particular provider.
Artie you are two to three or more years behind the power curve, in other words ancient history
