The type of widget installed on your website will determine what reviews are displayed.
The Review Display Widget (which is the free version) only displays reviews left on the My Listing page that have been published in Reputation Management.
The Review Display Widget Pro, on the other hand, displays reviews left by a customer on the client's My Listing page as well as those left on selected 3rd party sites such as Google or Facebook.
(Please note we are not able to display Yelp reviews).