Film trailers are banking on Net impressions

— -- The total amount of screen time amounts to little more than a teaser, but those few seconds may have turned the Indiana Jones sequel from a question mark into a must-see when it opens May 22.

Since the trailer's debut online less than four weeks ago, millions of fans have clicked through to watch the promo for Indiana Jones and the Kingdom of the Crystal Skull.

What they saw, observers say, eased any doubts about the star and the character.

"It does a great job in showing that Harrison Ford is back as Indy along with the character's trademark humor and action," says Mirko Parlevliet of movie news website ComingSoon.net.

As the number of people watching television or going to theaters levels off and declines, studios are depending more on the near-instantaneous spread and feedback of the Internet for the crucial role of attracting a finicky public to new blockbusters. "It's all about first impressions," says Harry Knowles of AintItCool.com.

A recent survey of moviegoers by the Motion Picture Association of America found that 73% looked for information about films online and that more than half of respondents (54%) saw ads or trailers online.

Traffic to sites with trailers increases seasonally as summer and holiday movies approach, says Alex Patriquin of Net traffic watcher Compete.com. Last July, it peaked as nearly 20 million unique viewers visited movie hubs on Yahoo, AOL and MSN as well as trailer sections of the Internet Movie Database (imdb.com) and Apple.com.

"Trailers build up momentum because people love to talk about the movies," Patriquin says. As fans become more accustomed to getting movie news online, studios realize they can "manipulate and supercharge buzz online."

For the January film Cloverfield, Paramount ran a Net-based viral marketing plan "that weaved an experience" around the apocalyptic monster film, Patriquin says. Most important, the campaign "kept the monster a mystery, pulling in moviegoers the first weekend who wanted to find out what he looked like."