Mine too, but I have to authenticate first. Did you enter your username and password?
My PCs forget after they're restarted.
I have various complaints with OSX sharing, including the lack of chroot jails (requiring various hacks that may or not work) but I think there is already a folder such as you require.
Go to the top level of your HD, then Users/user name/ and there should be a Public folder that others can open, without being able to open any other folders.