UPDATE 9/13 noon: see end of post Wonderful post by Cafe Hayek on the history of how the state imposed last names to supersede local practices ("Bill who lives in the east"), featuring an awesome essay on Cato Unbound by James C. Scott and a thoughtful response by Donald Boudreaux.
Query: which societies today still do not have permanent last names?
UPDATE 11:30am: thanks for the responses to the query! keep them coming. The James C. Scott thesis is that a permanent last name (i.e. the same across generations) is some measure of the "modernization" of the state. I think I feel an instrumental variable coming on here...
My own contribution: in Spanish and Latin American cultures, you have two last names, the first is the surname of your father and the second the surname of the mother. If you give only one of these names to identify someone, you use the first, not the second (I always complain to the American bookstore owners who file Gabriel Garcia Marquez under M instead of G).
UPDATE 9/13 12 noon: THANKS for all the great responses to the surname survey! Looks like we have an awful lot of societies that don't pass the James C. Scott "state modernity" test of having permanent surnames across generations.
Just to clarify: Scott was not necessarily arguing that this kind of "state modernity" was always good. The state wants it to collect taxes, which are not always a good thing, and maybe also to make it easier for the state Gestapo to keep track of everyone, which is even less of a good thing. Donald Boudreaux (see link in the Cafe Hayek post) has the insightful comment that even with this state control downside, permanent surnames also facilitate personal identification for many "gains from trade" transactions among private persons.