So many marketing companies, distributors, or directors themselves have no idea how to put an effective teaser together. A teaser that is inherently a short trailer, is not a teaser. A teaser with footage and/or dialogue from a previous film is NOT a teaser. A teaser with dialogue from the film, but no footage whatsoever and instead a stupid revealing of the logo for the movie or something like that is NOT a teaser. A well crafted teaser in my opinion offers you some dialogue and some footage from the film, but not necessarily of any correlation. An effective teaser should make you want to learn as much about that film as possible, but not give you anything concrete.
An effective trailer in my opinion is for Paul Thomas Anderson’s latest film, The Master. All I know is the movie has Philip Seymour Hoffman in it and Joaquin Phoenix, and has something to do with religion. This trailer doesn’t give anything major away, but between the music and dialogue, I am very pumped for this film.