Yotpo Rich Snippet Solutions
It has been tested on BigCommerce and Shopify.
A WordPress plugin has been developed to work with WooCommerce and WP e-Commerce. It is in the WordPress folder. A basic WooCommerce install was tested (one review).
To make the review scores accurate the Start Distribution widget needs to be enabled.
For it to generate valid review dates it needs the Yotpo date format set to YYYY-MM-DD. The setting is here: Tools>On-site->Reviews Widget->General Settings