Back in the early days of "summer" movies, all marketers really had to go on was the quality of the film and the visceral appeal of the subject matter, bolstered by word of mouth and critical reception. With so many more tools available to us today, we have tremendous new opportunities to try to generate excitement, but also to shoot ourselves in the foot. Part of me shudders to think how viral marketing would have been used to market "Jaws." Would we have mysterious photos and blogs popping up a la "Cloverfield" showing the results of shark attacks along the East Coast? A Yahoo group for one-legged swimmers? A Facebook application sponsored by Crest that lets you bite your friends? Would Paramount (in this case) have exhausted potential movie-goers to the point that when Chrissie desperately tries to climb onto a buoy in the opening, they just sit there numb and blasé??

We'll never know, but thinking about that offers some perspective on how to apply viral marketing effectively. It's all about building buzz in a way that appeals to the basest interests of your audience. You should know who they are, and you've got to trust your instincts that you'll come up with the best ways to speak to them.

And most importantly you've got to stretch your creativity to the limit to try to do something that hasn't been done before. That doesn't mean it needs to be complicated. Something as simple as a goofy but fun on-line quiz can do the trick if that's the best way to reach your target. Often, less is more, because as "Snakes on a Plane" has proven, if your marketing crescendo peaks too soon, you'll end up with lots of empty seats in the theater.

And sometimes all you need to rely on is a single image, like an ominous image of a monstrous fish coming out of the water.

John Conroy is a marketing consultant with Los Angeles-based Cooperson Communications.