Watch five minutes of Cloverfield

It is coming on January 18, or thereabouts. It is a new and monstrous phenomenon to frighten even the most seasoned of marketing men.

Already it is stalking the board-rooms of leading Hollywood studios, unleashing terror. It is the spectre of a film with no name, a film that may prove a peculiar truth in 2008: that the best way to market a product to a young and wired generation is not to market it at all.

Better, in fact, to say as little as possible about the whole project, but for a few well-chosen, ambiguous clues, and to let hordes of puzzle-solving, investigative bloggers and online-forum jockeys do the rest.

A trailer for the horror adventure film that is being referred to as Cloverfield appeared in cinemas in July, before showings of Transformers, a film with a notoriously tenacious fan base. The scene was a party in lower Manhattan, full of attractive young people, apparently shot on a handheld home-video camera. There is a loud noise, the lights go out, and like the amateur catastrophe cameramen of September 11, the partygoers head for the roof to see what has happened.

What they see is a colossal explosion, a fireball, and trails of sparks exploding around them. As they flee the building, a great round object bounces down Manhattan towards them, demolishing the occasional building, before coming to rest on the road. It is the head of the Statue of Liberty.

Addicts of this sort of cinema did a double-take. Where had this film come from?

The seemingly low-budget viral campaign for Cloverfield – the film apparently cost £15 million to make – has adopted similar tactics to a film from the high-budget end of the spectrum, due for release in the summer. Producers of The Dark Knight, known to legions of aficionados as the new Batman film, also attempted to maintain high levels of secrecy in shooting over the summer. Warner Bros posted a casting notice for Rory’s First Kiss, though the title was quickly rumbled as a fake when fans looked at the cast, which included Christian Bale and Gary Oldman. A curious marketing campaign for the film is under way, which borrows heavily from the world of alternative reality games, where clues are scattered online and in actual locations.

A series of “dummy” websites sprung up containing a cryptic clue to other sites. Fans who followed the trail were led to real-life bakeries. The first to arrive at each bakery was presented with a cake, with a phone number inscribed in the icing. Inside the cake was a bag marked Gotham City Police Department.

It seems as if the latest wave of films are trying to outdo each other in their cloak-and-dagger operations. Like the characters of a horror film, each of the hitherto-unknown actors involved in Cloverfield were kept in the dark. No scripts had been sent out, their agents were not informed as to the plot, and when they came to audition, they were handed scenes that had nothing to do with the film.

“We weren’t exactly clear about the characters we were playing when we signed on,” said Lizzie Caplan, who plays a character called Marlena, and whose previous credits included the role of Party Girl in the teen film Orange County and Beautiful Girl in one episode of the US comedy series Undeclared.

The scripts were watermarked to prevent anyone copying them, and each day producers would swap the latest pages for those of the previous day. The secretive nature of the entire operation was enough to spark enormous excitement, particularly when the producer’s name, tagged on to the end of the trailer, was J. J. Abrams, the man behind the television series Lost.

Since then an official synopsis has emerged on an official website, though it has added little to the general sum of knowledge, other than the precise proportions of the monster terrorizing Manhattan – apparently it is “the size of a skyscraper”.

The producers of this strangely compulsive phenomenon have emerged in recent days to give the movement a prod. Over the weekend, fans who subscribed to the e-mail list of Slusho!, one of the names under which the film has been registered, have been sent sonar images, perhaps of a deep-sea creature heading for Manhattan? On the social networking site MySpace, the film’s principle character has now appeared.

This evening, an official competition for the “most grabbed” video clip posted online will conclude, while trivia quizzes, compiled by fans, on the subject of this unknown film, are posted to entertain the growing fanbase.

After all this hype, some fear that the film itself will prove a letdown, although this no longer seems to matter. The build-up has probably been far more entertaining.

The witch guide to publicity

The Blair Witch Project

The acknowledged pioneer of online viral marketing campaigns, it was a horror film shot on a handheld camera and cost less than £13,000 to make. Online marketing suggested that the film was documentary footage of an actual event. It made more than £125 million

The Beast

In 2001 Microsoft and Dreamworks commissioned The Beast, a game disseminated on websites and e-mails, accessible only once players had solved complex problems. Intended to publicise Stephen Speilberg’s film A.I.: Artificial Intelligence, it was played by 3 million people

Snakes on a Plane

In 2005 a blogger heard of a new project involving the actor Samuel L. Jackson. Soon it had a life of its own: fans designed a logo and producers shot extra footage and apparently inserted lines suggested by the online fans

Watch five minutes of Cloverfield

Explore Film

• Film Reviews

• Trailers

• DVD

• London Film Festival

Editor's choice

• The 100 Best Films of the Decade
• 70 facts you didn't know about Marvel
• The 50 Biggest Movies Of 2010