But other than that little cozy feeling - what good is feedback to you as a seller?
Use Feedback as a Selling Tool
The most powerful way to use good feedback is to make sure your future customers see it. The best way to do this is in any of your social networking environments like Facebook, MySpace, twitter, newsletters etc.
When I get good feedback on a product I can re-list I almost immediately post to Facebook. I call these "What my Customers are Saying" posts. I copy the feedback exactly. For example a Facebook post may look like this:
What my customers are saying: Beautiful earrings, exactly as pictured. Fast shipping -- overall great deal!
Then I post a link directly to the re-listed item so the person reading the post can see what item the feedback was left for, and hopefully will click on it.
If you get enough of these, your Facebook fans will start to see a pattern of happy customers.
In addition, I include generic What my Customers are Saying quotes in my email newsletters. I may, or may not include links to the product in this case. But I try to have a small section of my correspondence show my existing and hopefully future customers that I do have current happy customers.
What if I'm not getting feedback?
Many buyers may not even be aware that they can or should leave feedback. So, with each purchase encourage your customers to let others know they are happy with their purchase.
But - make sure to tell them to contact YOU first if they are unhappy. This gives you the opportunity to resolve any potential problems before a customer has left feedback. This way, even if a customer wasn't initially completely satisfied, they may still end up leaving positive feedback because you exhibited exceptional customer service.
To help encourage my customers to take the time to leave feedback, I purchased special business cards just for this purpose. I used VistaPrint to get very inexpensive cards and include them with my standard business cards. I do not use these as handouts at shows, but only for online purchases.
Here is an example of the card I use (click to see larger image). I have two main online stores, which is why there are two store addresses. Tailor your card to your business. The important parts of this card are: 1.) Tell the customer to contact YOU if there's a problem. 2.) Encourage the customer to leave feedback if there's not.

Then - take that feedback and turn it into a selling point.