Administrator vs. Desktop accounts

[pigpoked at Safe-mail.net]

Within System / Admin / Users and Groups I add a new user.

Whether I assign the user a Desktop account with administor the system option checked, or choose Administrator which has all entries checked by default, what is the difference?

What is the defining cut and dry difference between Admin and Desktop choices within Users and Groups? Administrator cannot equal root as I added a user as Administrator and sudo remains a requirement to issue root commands.

If a new user is added as Administrator vs. Desktop with admin box checked, any added dangers in using this account with internet facing programs?