The passage that we see Kathleen Kelly reading during her bookshop's story time to a group of kids (including Joe Fox's aunt and brother) is from "Boy: Tales of Childhood", an autobiographical children's novel written by Roald Dahl.
The children's bookstore scenes in the film were actually filmed at Maya Shaper's Cheese and Antique Shop on 103 West 69th Street. The film makers wanted to use the antique shop because it had the quaint, homey feel they were going for. They sent the owner of the antique shop on vacation for a few weeks and while she was gone they turned the store into a children's bookstore. After filming was finished, they put everything back the way they had left it, and it became an antique store once again.
The scene where Joe accidentally closes the door of Kathleen's shop on the balloons was unscripted. Tom Hanks actually did that, and ad libbed the line, "Good thing it wasn't the fish." Nora Ephron thought it was so funny that she kept it in.
Joe Fox (Tom Hanks) is obsessed with The Godfather (1972), and frequently uses dialogue from it to shape his philosophy on life. In the Coppola Restoration Godfather DVDs, Alec Baldwin claims that Hanks and Rob Reiner are both Godfather aficionados who have been known to host viewing parties where the attendees do drinking games and quote famous lines while watching the film.
The location of Fox Books in the movie is actually the location of a real-life Barnes & Noble, on Broadway and 83rd Street on the Upper West Side. The Barnes and Noble generated considerable neighborhood opposition when it opened in the early 1990s, as many feared it would drive a local bookseller, Shakespeare & Co. on 81st Street, out of business. This is exactly what happened.
Joe Fox's grandfather mentions that long ago, he briefly shared a pen pal romance with the store's previous owner, Cecilia Kelly (Kathleen's mother), and that they only communicated through letters. This may have been a reference to the movie's predecessor, The Shop Around the Corner (1940), starring James Stewart and Margaret Sullavan, or possibly the famous book and the movie 84 Charing Cross Road (1987) of the same name, with Anne Bancroft and Anthony Hopkins as a female customer in New York and a male employee of the bookstore at that address in London.
The movie's opening and ending titles make use of commonly seen computer images of the time, specifically Windows 95/98. The ending title song, which begins just after the words "The End" appear on the screen, starts with and adaptation of the "startup" sound from Windows 95.
Kathleen Kelly's bookstore in the film was based largely on Manhattan's Books of Wonder in Chelsea on 18th Street. Meg Ryan worked the counter at Books of Wonder for a day as part of her preparation. Decorative props from the film can still be seen at the store.
Nora Ephron arranged for Meg Ryan and Heather Burns to work in a real New York City bookstore in preparation of their roles prior to filming. The store was Books of Wonder in Manhattan, and the jobs lasted for about a week.
Meg Ryan's character, Kathleen Kelly, uses a Macintosh PowerBook G3 "Kanga", (introduced 11/97), or a Macintosh PowerBook 3400c, (introduced 2/97) in the movie. The exact model she used can't be determined from looking at the outer plastic case, as both machines used the same plastic case.
In the party scene, Tom Hanks' character responds to Kathleen's comment "that caviar is a garnish!" by scooping up all the remaining caviar for himself. In the movie Big (1988), Hanks' character tries caviar at a party, which he hates; he spits it out & wipes his tongue with a napkin.
The trivia items below may give away important plot points.
Could arguably be a modern re-telling of Jane Austen's "Pride and Prejudice," of which Kathleen is a fan. Joe Fox mimics the story's male protagonist Mr. Darcy (Pride), while Kathleen Kelly mirrors the female protagonist, Elizabeth Bennett (Prejudice.) Like the novel, the two meet under casual circumstances only to end up at odds with each other due to differing views and opinions. Like Elizabeth, Kathleen becomes determined to hate Joe Fox due to his proud disposition. But, their continued encounters lead them to eventually fall in love. The redeeming factor of the novel however, is inverted in this film. In the story Darcy finally "wins over" Elizabeth when she learns of the noble service he selflessly performs for her family. Joe Fox on the other hand, does Kathleen a great "disservice" by putting her out of business; making the story somewhat unique as the two fall in love in spite of this.
The song at the end of the film when they are standing on the bridge is "Somewhere Over the Rainbow". A clip of this song is played in the previous movie with Meg Ryan and Tom Hanks, Sleepless in Seattle (1993).
This movie's screenplay is based loosely on the 1940 movie The Shop Around the Corner (1940), starring James Stewart and Margaret Sullavan. Kathleen's store is named The Shop Around the Corner, the two main characters are latter day (mail) and present day (email) "pen pals"; they both know they are falling in love with their respective pen pals; when the man realizes who the woman really is, he pursues her, but is not sure the love match will work; in the end, they find they belong together.