The only thing that differentiates users that manage the site is their roles and the permissions associated with their roles. Users who register on a site don't get any roles with special permissions unless you add them to the roles. I sign into this site the same way you do but I can edit content and you can't because you are not in a role allowed to edit content. The only reason people register on this site is to show their support for the project (since we want them to register), to be able to post in the forums, or to purchase add on products.
So the kinds of users are:
- anonymous visitors who are not signed into the site and we don't knw who they are
- users who sign into the site
The second group only has roles granted to them and can only do what their roles allow but there is only one kind of user, they are all registered users who have an account on the site and they may have different roles and therefore different permissions.
Now you may have a site where the only people who do login are the ones who manage it if it is just a brochure site not using forums or ecommerce. For a site like that you could either put the sign in link in the footer where less people will notice it or remove the sign in and register links from the layout.master file and the users who manage the site would have to just know that they can login by going to /Secure/Login.aspx. But there is no way to show the links to just some users because you don't know who they are until they login. If I'm a person in the adminsitrators role the site does not and cannot know that until I login.
Hope that helps,