Critics will have to wait. Yesterday, the only ones hissing were snakes. Yes, those snakes. The ones on a plane.

After months of Internet buzz, audiences at Comic-Con in San Diego got the biggest bite yet of Snakes on a Plane, thanks to an exclusive presentation — including new footage of the film — attended by Samuel L. Jackson. That’s in stark contrast to New Line’s decision to not screen the movie in advance for critics. And it’s just one more example of Comic-Con’s burgeoning clout.

Go ahead, balk. But for proof of what a Hollywood hub this comic-book convention’s become, look no further than the A-listers mingling amid the costumed ranks of Siths and superheroes. In addition to Jackson, there’s Hilary Swank, touting her forthcoming horror film The Reaping, as well as Nicolas Cage and Eva Mendes, to appear today to push their Marvel-based Ghost Rider.

Sometimes a celebrity’s not even here for a movie. Rosario Dawson showed up to talk about a comic book she’s penning called Occult Crimes Taskforce. Adam Brody, uber-geek Seth on The O.C., is chatting up a comic he’s co-writing. Richard Donner, director of the 1978 Superman film, is expected to be announced as co-scribe of the Man of Steel’s comic book. Donnie Darko director Richard Kelly is here to drum up support for Southland Tales, his latest film, for which he wrote three prequel graphic novels.

The nerds didn’t just get revenge; they got cool. And there are enough of them — blogging and podcasting and posting — to help (or hurt) a movie or TV series before it even launches. So just as studios courted the religious right after the success of Passion of the Christ, geekdom now comprises its own powerful constituency. And for them, Comic-Con is Mecca.

"These Comic-Con people, they have their ear to the ground. They are tastemakers," Marlon Wayans, who’s also penning a comic, told Hollywood Reporter.

But that doesn’t mean the convention’s newfound respectability has robbed it of its undeniably goofy charm. A stroll through the San Diego Convention Centre, where the four-day event wraps up tomorrow, uncovers not only fans of all shapes, sizes and outfits (crimefighter and stormtroopers are favourites) but a who’s who of ’70s sci-fi, from Buck Rogers’ Erin Gray to V’s Marc Singer. The very sight of Lou Ferrigno is enough to bring a tear to your eye, harking back to a simpler time when all you needed was green paint to be an incredible hulk. And a simpler time when Comic-Con had comics, toys and maybe a Klingon or two. Now, it’s huge — more than 100,000 trekked here last year. And with every new pointy ear or cape and cowl, the convention’s significance grows in the eyes of filmmakers seeking to shore up their base like politicians before an election.

When director Bryan Singer wanted to lift the veil of secrecy surrounding Superman Returns last July, he halted production in Australia to come here to do it with an exclusive preview (much as Snakes is doing this year). Ditto director Sam Raimi while Spider-Man 2 was being made.

So it’s no surprise both Singer and Raimi will be back to discuss the recent Superman Returns and the forthcoming Spider-Man 3.

Other films being previewed include Flyboys, a First World War adventure from Independence Day producer Dean Devlin; Children of Men, starring Clive Owen and Julianne Moore, with director Alfonso Cuaron on hand; and 300, the adaptation of Frank Miller’s graphic novel.

Two years ago, Lost bowed at Comic-Com, winning raves months before it became a mainstream hit. Hoping to repeat that success are a number of fall TV series, chief among them NBC’s Heroes, about ordinary people who discover they have super powers. The network is debuting a 72-minute version of the pilot exclusively for Comic-Con. Also premiering is CBS’s Jericho, about a postapocalyptic world.

Lost’s co-creator and executive producer Damon Lindelof will be joined by Jorge Garcia (Hurley) and Daniel Dae Kim (Jin) this morning to hype the third season. Veronica Mars star Kristen Bell will participate in a panel for the cult favourite, while Battlestar Galactica’s Edward James Olmos, Lucy Lawless and Mary McDonnell will discuss the third season of their series — which, like Comic-Con, has swapped camp cheese for mainstream respectability.