Now the FTC is trying to limit the use of testimonials:
Under the revised Guides, advertisements that feature a consumer and convey his or her experience with a product or service as typical when that is not the case will be required to clearly disclose the results that consumers can generally expect. In contrast to the 1980 version of the Guides – which allowed advertisers to describe unusual results in a testimonial as long as they included a disclaimer such as “results not typical” – the revised Guides no longer contain this safe harbor.
But remember that testimonials can be used for good or for evil. Jenny Craig, the legitimate weight loss system, uses testimonials throughout their website, e.g.
Kristen S. Age: 32
Weight Lost: 28 lbs*
I had a baby not too long ago, and found myself struggling to get the weight off. It was easy to put the weight on, but getting if off was another story. I love caring for my baby, but would ...
*Results not typical
Now it looks as if they will have to qualify these testimonials with formal statistical studies, raising the cost and reducing the effectiveness of their weight loss message.