There is, somewhere, a fine line when it comes to marketing your product or service. You want to be thorough in selling all the cool stuff you can do. But you don't want to overwhelm those on the receiving end of your message.

New research might shine a light on where exactly that line lies. Two business professors -- Kurt Carlson of Georgetown and UCLA's Suzanne Shu -- asked the question: Just how many good things are potential customers willing to hear?

Sales Secret

Their paper, titled "When Three Charms but Four Alarms: Identifying the Optimal Number of Claims in Persuasion Settings," says the answer is three. The study presented a group of about 300 students with written descriptions about five different products or services, ranging from an ice-cream shop to a politician. But the samples differed in the number of positive claims attached to each description, ranging from one to six.

For example, in the case of the ice-cream shop, they were told, if their description included all six claims, that the shop offered better seating, faster service, more flavors, lower prices, cleaner, and bigger servings than before.

The students overwhelmingly said that for each product, they became increasingly skeptical of the claims after the third. The students also indicated that they felt better about an establishment that made three claims rather than one or two.

The takeaway from the study is clear: Don't sell yourself too hard. But sometimes you might want to even take it a step further. Tom Szaky, CEO of recycling company TerraCycle, said in the New York Times last year that he takes it upon himself to own the negatives when selling.

"We consider TerraCycle a premium service," he told the Times. "For that reason, we always highlight that our cost is higher than other solutions, such as sending waste to landfill. But then we emphasize that the benefits of working with us may be worth the expense. Of course, there is a fine line--you can volunteer too much negative information and kill the deal. Negative information is like salt on one's food. It should be applied in moderation."