Shared hard drive with user-level permissions
The "Sharing and Permissions" attributes are directly related to other users on your computer. In System Preferences, you can enable "File Sharing" which allows others on your network to connect to your machine and access folders that you designate.
In the configuration for File Sharing, you designate "Shared Folders". You can set them up to be read (or even written to) by "Everybody" or only designated users. Those designated users would need to have an account on your machine to authenticate themselves; the name of their account on their own machine isn't the factor here.

None of this requires Lion Server.