Der Independent hat einen interessanten Artikel über die Wissenschaft und die Marketinghintergründe von Trailern. Hier ein paar Auszüge.

“Teaser trailers can be launched up to a year ahead of release,” explains London-based publicist Rupert Fowler, who began his career in LA and has worked on many film campaigns. “Nearer to release there can be as many as five different versions, varying in length and concentrating on specific characters or themes, such as romance, suspense or action.”
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The trailer came into being in 1913 when the Loews Cinemas company created one for the musical, The Pleasure Seekers, which was playing on Broadway. But the early days of trailers were usually maladroit and audiences immediately knew they were being sold something. The Bishop’s Wife in 1947 gave a knowing nod to such tactics with a self-referencing trailer staring David Niven and Cary Grant on their way to film a promo for the movie.

Until the 1950s, American trailers were produced by the National Screen Service, although some directors such as Alfred Hitchcock and John Ford liked to produce their own. In the 1960s film directors took a keener interest, leading to more stylish trailers. Plot spoilers in trailers still existed into the 1970s although trailers were less brash than today. “This is Universal’s extraordinary motion picture version of Peter Benchley’s best-selling novel, Jaws,” intoned the gentle voiceover on a trailer for Speilberg’s shark fest which, during its three minutes, showed so much footage and dialogue, it was akin to an abridged version of the film.
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Over the years, trailers have been seen as worthy of study.

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“They play on emotional impact, set up situations, and produce an overall feel, both aesthetic and emotional, very quickly,” says film expert Dr Kriss Ravetto-Biagioli, of Edinburgh University.

And some can be better than the films. “George Lucas’ Star Wars prequels were lousy but the trailers were incredibly stylish and expressive,” says Daniel Hesford, who is writing a thesis on the subject. “They used minimal percussive soundtracks, musical cues from the famous score, skilful montages and the best, most expressive and aesthetically spectacular shots from the films themselves.”