What needs to be in place for Product Recommendations to work?

For product recommendations to work, the following rules apply in a standard data configuration.  

1. Items must be flagged "Active = 1". Please note that the Active flag is the primary way to disable a product from being recommended regardless of inventory levels.  If inventory is 0, a product could still be displayed if "Active = 1" for that product.
2. Image URLs must be available.

See the field descriptions below: