Everybody who accesses a server, no matter whether locally or externally, by FTP, SHH or similar, requires a user account on the server. Each of these user accounts is associated to a group. Examples of groups which can often be found on a web server would be "daemons", "user", "root", "nobody". Often there is a separate group for the Apache web server in which only the Apache or the Apache and the FTP users are located. Important: Everything done on a system and every program which is launched is executed under a certain user name. The web server, too, accesses files with a user account.

When you create a new file, it is assigned to your account as file owner. At the same time the group "user" is also assigned to the file. Every file belongs to a system user and to a system group.