How it works
The recently viewed products module works like a LIFO queue (Last In First Out.). The last seen product becomes first in the list, and previously viewed products move down the list. You can think of this as a pile of cards where you only ever add a card at the top. The number of cards in the pile is limited, and cards at the bottom are discarded as necessary to maintain the total count. The total count is your howManyToStoreInMemoryproperty. The number of cards you display is your howManyToShow property.
If a visitor repeatedly comes back and looks at the same product, the module will just move the item from its current position in the list up to the top, whenever that product page is viewed.
