What is Staff user account

Staff is the default user group for you that is assigned for files and folders that do not have admin group membership. For example if you install an application by drag and drop it automatically takes on the following privileges:

Owner=you with r/w
Group=staff (which is just you) with r/w
Everyone with read-only

An application installed via the Apple package installer takes on the default privileges of the Applications folder which are:

Owner=system with r/w
Group=admin with read only
Everyone with read-only

A good rule to follow is "Don't change permissions unless you really know what you are doing." If you have permissions problems related to system files installed by the OS X installer, then use Disk Utility to repair permissions.

The "admin" group consists of all users who have administrator accounts. Removing the Everyone entry will not give you any rights and should not be done.

Another good rule: "Leave well enough alone."

staff is a group not a user. it's the default group for every user in leopard and snow leopard. do not touch and don't delete it. it's quite normal to see it. by default all files and folders you create should have staff group with read permissions.