Carpe Diem. Seize The Day. Make Your Script Super-Quotable.
It's no surprise that a film so eminently quotable would inspire some fandom.
The American Film institute voted the quote "Carpe Diem. Seize the day, boys. Make your lives extraordinary" as the 95th greatest movie quote of all time. While the character wasn't the first to coin the phrase "Carpe Diem" (Horace was, all the way back—and we mean way back—in his Odes), it's definitely one that, with the help of Dead Poets Society, has become pretty widely used.
The actors also inspired fans…especially Robin Williams. After his death, fans and fellow celebrities took to Youtube to salute their captain the same way the students do at the end of the film.