User subfolders

[Guest]

In Windows 7 under the Users folder there are some folders with a lock before it. The folders are: Default User and Public and also All Users.

What i am wundering about is:

In WIndowsxp the first logon user gets the local administrater profile, because the administrator profile becomes the default. The next new users that logs in to the client gets the defaul user profile. How is that arranged in Windows 7?

I see a default user folder where i can't get in. There is also a default folder, and it seems this is de profile you get when you are new to the client. But where is the default user folder for?

And the All users profile because there is a public folder, i thought the public folder is the all users folder from windowsxp?