I meant surnames. Sorry to be vague--I figured everyone knew I didn't mean given names.
And if everyone has the same surname, it's effectively the equivalent of no one
having a surname...
Not necessarily. Sikhs aren't limited to only two names; they can have a third. And there are cultures that have no surnames in the Western sense but have long strings of given names, patronymics, and so forth. For instance, the man that Westerners called "Saddam Hussein" was actually Saddam Hussein 'abd al-Majid al-Tikriti. "Hussein" wasn't his surname, since he had none; it was just his second given name. By Arabic naming convention, he was properly referred to simply as "Saddam" (his ism
or given name), but the rest of his name served to distinguish him from other Saddams. Hussein was his father's name, 'abd al Majid means "servant of the Glorious One" (one of the 99 names of God
; most Muslim names have some form of "servant of God" in them), and al-Tikriti means "of Tikrit," his place of birth.