When the trailer isn't trash

SMALL PRINT:Last month, Mission: Impossible – Ghost Protocoldefied the odds (an unfashionable star, strange punctuation in its title) to become one of the biggest hits of the Christmas season, both State-side and internationally. Hooray! Tom Cruise is back! The franchise is still fresh after four films! Champagne and bonuses for all! But wait – like all good film narratives, there was a twist.

Apparently, one reason for the film's strong opening weekend was that it included exclusive preview footage for the next Batmanfilm, The Dark Knight Rises. This is not as crazy as it sounds. Enthusiasm is so feverish for the bat-brand that tickets went on sale this week in some American cinemas for opening weekend in July. And some opening-day showings are already sold out.

This would not be the first time that audiences went to see one film just to see a trailer for another. Way back in 1988, The Dead Pool(the final Dirty Harrymovie) enjoyed an unexpected spike in early ticket sales, partly due to the inclusion of (yep) a trailer for Tim Burton's Batman.There were even reports of audience members springing from their seats and leaving before the final Clint Eastwood movie began.

As if the above anecdotes weren't enough to remind you of the power of a good brand name, remember (if you dare) the hype for the Star Wars prequels. Before The Phantom Menacewas exposed for the mess that it is, there was much discussion online of attending non-Star Wars films to catch the Phantom Menacetrailers.

Unfortunately, this remains an inexact science – largely because movie audiences are usually surveyed after a film has finished, so those who pay for tickets and leave before a film starts often slip through the net. But a quick scan of the internet, and especially message boards on imdb.com, shows that the phenomenon exists.

It’s the stuff that Hollywood dreams are made of – franchises so popular that they can generate ticket sales for completely unrelated films.