Users rate merchants on a five-star scale.

Each merchant rating has an Overall rating, as well as five Component ratings that reflect the merchant's performance in specific areas: Price, Shipping Options, Delivery, Ease of Purchase, and Customer Service.
Here's an example of how a merchant rating appears on Yahoo! Shopping:

More information:
- What are merchant ratings and reviews?
- How is the “Average Merchant Rating” calculated?
- What does the number of ratings indicate?
- Is every merchant rated?
- What does the “Buyer Protection” icon mean?
- What does “Not Yet Rated” mean?
- What does it mean if a review is from a “post transaction survey?”
- How do I submit a merchant rating and review?
- Can I submit more than one review for a merchant?
- What are the guidelines for writing a review?
- Can I include links or other HTML in my review?
- Why isn’t my review showing up?
- How often are merchant ratings and reviews updated?
- How do I report an abusive, off-topic, or otherwise objectionable review that I think should be taken down?
- Can I edit or delete my review?