Reading the amazing The American Language by Henry Louis Mencken is a fantastic treat. On discussing American proper names, he references an article in American Speech by Ms. Miriam M. Sizer talking about how given names become all the more important - so that even the priest is known by his first name - in areas of "excessive inbreeding" (p. 523 of The American Language). The legendary Mencken continues:
"Many of the usual American given-names are in use, but sometimes the supply that is locally familiar seems to run out. Miss Sizer's novelties include Nias, Bloomer, Tera, Malen, Lony, Guerdon, Brasby, Ather, Delmer, Rector, Doley, Elzie, Ivason and Elmer Catholic. 'A man who was a great admirer of the James brothers," she says, 'named his boy Jesse-James-and-Frank. Another ... named his boy Christopher-Columbus-Who-Discovered-America.'"
Simple but incredibly intuitive. One surname can easily come to dominate a small region in ways in which given-names are very unlikely to. Rather than cause confusion in the listener, the talker simplifies by using given-names rather than family names. But even this can be tricky when there are only so many familiar first names sharing a few surnames, so rather than change heritage-carrying surnames, children are named in novel ways.
Names are a growing area of economic research. Steven Tadelis of Berkeley-Haas has analysed firms' names as tradable carriers of reputation and Steve Levitt and Roland Fryer have researched the causes of distinctively-black names. Alas, I do not see anything as important in the snippet from Mencken, but it is nice and logical and very much worth sharing.