Dueling Dubs: The film was originally dubbed by ADV (they're pretty much the official licensor for all of Makoto Shinkai's works, in both their past and current incarnations) and released to DVD in early 2008. Not long afterward, ADV had their infamous Japan-instigated collapse and lost the rights. Crunchyroll snapped up the license, had the film redubbed at Burbank's Bang Zoom! Entertainment, and re-released it on DVD the next year with assistance from Bandai Entertainment.
As a result, the original ADV release - whose dub was generally better received than BangZoom's - is very much a case of Keep Circulating the Tapes.
Technology Marches On: The first act occurs in the early 1990s, and as such, cell phones and email are still relatively rare. As the story moves through the second and third act, these technologies become more commonplace.