Description: Robert Downey Jr. is billionaire arms industrialist/inventor Tony Stark, who creates an armored suit that transforms him into a flying superhero. Also starring Gwyneth Paltrow, Terrence Howard and Jeff Bridges. Directed by Jon Favreau.

Traffic: 3.7 million streams on Yahoo Movies since first trailer launched in September 2007.

Comments: The trailer, says Mirko Parlevliet, editor in chief of www.ComingSoon.net, "shows that they pulled this off. It features excellent special effects and shows that Robert Downey Jr. is perfect in the role."

Tom Burns of entertainment site www.TheDeadbolt.com agrees. "It is hard to exaggerate how effective the early trailers for 'Iron Man' have been. The best compliment that I can pay the 'Iron Man' marketing team is that, when the last trailer was released, my wife, who is not a superhero fan, grabbed my arm and said, 'I'll go see that with you.' É All the superhero CGI stuff is just icing on the cake. Good movie first, superhero origin story second."

Description: About 20 years after "Indiana Jones and the Last Crusade," Jones (Harrison Ford) travels to South America to thwart the Russians, including Agent Spalko (Cate Blanchett), in a race for supernatural artifacts.

Traffic: More than 5 million streams on Yahoo Movies since Feb. 14.

Comments: "The trailer does a great job in showing the return of the character by saying what he has done before, with the music, the shadow of the hat and more," Parlevliet says.

Knowles says he still has "some nitpicks with the trailer. I wish the music and sound effects were mixed a little better. I think when the 'Indiana Jones' theme comes in, I wish it just blew me out of my seat. When the whip cracked, I wanted it to feel like it snapped my ear off. But the trailer did exactly what it was supposed to do."

Description: Mark Wahlberg stars in M. Night Shyamalan's latest about a teacher and his family on the run amid an environmental apocalypse.

Traffic: 200,000 streams on Yahoo Movies since February.

Comments: Because Shyamalan "lost a lot of his buzz-worthiness after 'Lady in the Water,' " Burns says, "the goal of 'The Happening's' trailer is essentially to revive the sense of excitement and anticipation that surrounded his past movies. However, it doesn't really do it for me. The trailer basically looks like what would've happened in 'Signs' if Mel Gibson's family had left their house."

Not so, Parlevliet says. "It keeps the thing attacking us a secret while building up great tension showing the character's increasing fear about not knowing what is going on."

Knowles says the trailer works but may not prepare moviegoers for the brutality in the film. "I think it's his most revealing trailer," he says. "But I don't think the audience really understands yet how afraid they are going to be when that wind cuts through the wheat field."

Description: Batman (Christian Bale) faces off against the Joker (the late Heath Ledger).

Traffic: 7.4 million streams on Yahoo Movies since the first trailer launched in August 2007.

Comments: "The teaser trailer set up the Joker as a formidable foe (and the full-length trailer) gives a true feeling of continuance from the first film," Parlevliet says. "It also doesn't hold back on showing the action the fans are expecting."

Knowles says he saw the trailer again recently before watching "10,000 B.C." in a theater. "People were extremely excited to see (Ledger) and that movie. The trailer works magnificently."

The trailer accomplishes its mission of "convincing the audience to forget Jack Nicholson and accept Ledger in such an iconic role," Burns says, but its Batman-vs.-Joker focus may backfire: "It very purposely ignores (district attorney turned villain) Harvey Dent/Two-Face (portrayed by Aaron Eckhart). If the final film primarily features Harvey Dent, and the Joker is just a side character with not a lot of screen time, fans might feel cheated."