When you begin to sell your products online, you know you’re going to have to overcome the natural disbelief the market will have regarding what your product will do for them.
Tools available to help include: case studies, physical demonstrations, pictures, financial statements, and testimonials. Of these, testimonials can be the most powerful weapon in your arsenal. Testimonials are so important because what others say about you is ten times more believable then what you might say about yourself.

And the best kind of testimonial is a “specific results” testimonial. That means your customers explains in detail the specific results he/she achieved as a result of using your product. These results could be dollars earned, percentage increases in business, or any number of other things.
The more specific the better. 92.7% increase in sales is way more believable than saying more than 90%. $34,997.98 in sales last month will serve you far better than saying over $34,000 in sales. Specifics help sell, generalities don’t.
Online, video testimonials are the most powerful form because people can see and hear your customer in addition to reading the written comments. But you should also use audio testimonials and written testimonials. And you should include them in your outgoing product shipments as part of your stick strategies.
Testimonials should, at the least, identify the customer by full name and city and state. Online you might also find the URL of the commenter. If you choose to list the URL make sure it’s not an active link so you don’t risk leading the reader off your website.
According to Jack Trout in The New Positioning, a testimonial attacks the insecure mind on several emotional fronts — “a trifecta of vanity, jealousy, and fear of being left out.”
You really can’t overdo it on testimonials. Internet marketer Marlon Sanders has hundreds of product testimonials on his website. A disc full of testimonials is frequently included by information marketers, along with offline sales letters.
Testimonials are a must in your marketing.