As Robinson Meyer reported yesterday at the Atlantic, Facebook compiled the answers users in six countries gave to a question that went viral on the social media site over the summer: “What books have stayed with you?” J.K. Rowling’s “Harry Potter” series topped the list of most-mentioned books in Italy, the Philippines, Brazil, India and France and came in at No. 3 in Mexico.

QuidCon is the annual conference of the International Quidditch Association, now in its third year. Quidditch enthusiasts congratulate each other after playing the Harry Potter-inspired game in Fairfax in June. (Marvin Joseph/The Washington Post)

I adore the “Harry Potter” series and, in fact, spent the first part of my holiday break last winter marathoning and live-tweeting all seven books in a row. But I am fascinated by their persistence, in part because of how much they improved as Rowling continued to write them: the characterization gets deeper, the ideas more sophisticated, and Rowling’s prose improves dramatically from the early awkwardness of “Sorcerer’s Stone” to the occasional passages of “Deathly Hallows” that achieve a real lyric effect. (And yes, I think I am the only Rowling reader who quite likes the extended camping sections of that final book.)

Certainly I think one reason Rowling’s novels have a strong international audience is that she makes a studied effort to have the “Harry Potter” novels be multicultural and multinational, even if those details come in at the margins of the novel, rather than at the center. Harry Potter, Ron Weasley and Hermione Granger may all be white Brits, but their friends at the Hogwarts School of Witchcraft and Wizardry include Dean Thomas, who is black, and Padma and Parvati Patil, who are British students of South Asian origin.

When Harry learns he is a wizard, his world gets bigger not just in that he learns that magic is real, and not just in that he is liberated from the cupboard under the stairs, but in that he starts to be exposed to people from countries beyond the United Kingdom. “Harry Potter and the Goblet of Fire” takes Harry and his friends to the Quidditch World Cup, where they learn more about how national rivalries play out in wizarding communities. The Triwizard Tournament that takes place at Hogwarts in that same book gives the main characters sustained exposure to students from other countries, and to the different ethical stances those other schools take on the dark arts.

I think this multicultural and internationalist approach is certainly part of the draw, and one more artists could learn from. But ultimately, I think the sustained influence of “Harry Potter” is probably more a function of a larger shift in culture that is happening everywhere at once. At a moment when our culture is fracturing into tiny niches, fine-tuned to meet the exact needs of a small but passionate group of people, “Harry Potter” feels like it might be one of the last truly global book phenomena.

There are 450 million copies of the Harry Potter books in print around the world. In the U.S. and U.K. alone, 11 million copies of “Harry Potter and the Deathly Hallows” were sold on the first day of the final book’s publication.

And those numbers do not necessarily capture the mass intensity of feeling for the Boy Who Lived. In college, I worked the book release party for “Harry Potter and the Half-Blood Prince” at one of the largest Barnes & Noble stores in the country, spending almost all day watching the people in line talk to each other, buoyed by their shared enthusiasm. One such book release party shows up in Richard Linklater’s lovely movie “Boyhood” as a cultural reference point, one that is probably far more recognizable than the main character’s other passing enthusiasms.

This, I think, is why the “Harry Potter” novels have stayed with us. We feel connected to J.K. Rowling’s mischievous, sensitive, brave main character, of course. But Harry is also one of the last characters through whom we could feel connected to each other.