Q. I'm curious about the viral marketing campaigns for many big-budget movies (such as "Cloverfield" as well as the "Batman Begins" sequel "The Dark Knight"). "The Dark Knight" uses Web sites that include puzzles in order to unlock stills or pictures from the movie. One allowed people to enter their e-mail addresses to get a coordinate. With the coordinate, they could enter it at the Web site and remove a pixel from a vandalized picture of Aaron Eckhart (as Harvey Dent from the film).

As more people did this, more pixels were removed, and at the end, the first photo of Heath Ledger as the Joker was revealed underneath. Besides this, there have been scavenger hunts that would ultimately end in more photos being released and lead to Web sites revolving around the movies' events and mythology. Do you believe that more studios will use this tactic to market their product?

Jeremy Flores, UCLA, Los Angeles

A. "Viral marketing" refers to a strategy that tries to involve a movie's target audience in talking up a movie among their friends. They tell others about the Web sites, the audience grows, word-of-mouth spreads, and the campaign rolls under its own momentum. It is essentially a practical application of Richard Dawkins' theory of "memes," which are to ideas as genes are to heredity. He argues that certain ideas, beliefs, songs, images and superstitions spread from mind to mind and, like genes, the hardiest survive.

Rogert Ebert

So there you go. I thought at first that Ebert had misspelled "heartiest," but a quick search revealed that he used a perfectly legal alternate spelling. I found that interesting for no reason in particular.

Jeff

P.S. Happy Groundhog Day tomorrow. Speaking of Ebert, celebrate by watching the movie again.