In Electronics: A customer viewing a tablet may see frequently viewed together recommendations for other tablets and related devices that customers who viewed this one also viewed. Filter by category, to show only the same type of device.
In Toys: The toy currently being viewed will have a recommendation of similar toys that those who viewed this toy also looked at while shopping. Filter based on price, such as only show products more or less expensive.
In Fashion: When a customer is viewing a pair of pants, the recommendation will show other similar pants and items that users who viewed these pants also viewed. You can also filter so that it only shows the same color, brand, etc.
In Travel: When a customer is viewing a flight, the algorithm can show them similar flights which were viewed by others who viewed this same flight they're looking at now. Use the shopper's search settings to filter the recommendations.