In recent history, Hollywood had tried this stunt before.
Remember the Godzilla of 1998? Audiences were teased with a tail
here, a roar there, and the filmmakers pretty much had the monster
kept under tight wraps. Until it opened, and because it failed to
live up to its hype, and didn't meet everyone's expectations of how
the good old Japanese lizard would look like and behave, it tanked
at the box office. Now, Cloverfield adopted similar strategies in
having us hear a roar, and to witness its destructive powers,
without a visual clue of what it looked like. Did it deliver?
Continues at
http://anutshellreview.blogspot.com/2008/01/cloverfield.html